Fictional technology creation guide

Story comes first

Before we even begin delving into the whole technology creation process it's important to point out that your story should still come first. Everything has to serve a purpose in your story, so while you may have hundreds of ideas for all sorts of technological gizmos and gadgets they don't have to be mentioned right at the first possible chance of a character noticing them, if at all.
Consider the following: Let's say you're taking a subway to a city center. With you on the subway are many other people. Some reading newspapers, some reading books, some listening to mp3 players and so on. There are all sorts of advertisements both on the subway and on its route. Billboards, fliers lying about and so on. The subway also has various displays showing its route, where on the route it is, the next stop and so on. During your trip your smart watch notifies you as you've received a text message on your phone.

All of the things I mentioned are reflective of how far technology has come today. In a futuristic setting all those things will likely be either more advanced or replaced with something better, but did we really need to know all these things if this was to be written as a scene in a story? No, definitely not. The main point is that the character, in this case you, is traveling using public transportation and they received a message. In most cases the subway and the way you receive the message will give the reader plenty of information about the setting. If the people in the subway (and the stuff they use) are not important to the story don't bother describing them for the sake of creating a setting or any other reason (besides story) for that matter.
"But my readers need to know how great this transportation technology I've come up with is. Or how my story universe has people with bionic eyes." Do they? If it's not crucial to the story they probably don't.

The point is to not add and describe technology for the sake of trying to make your world seem more futuristic. A few elements is all it takes to get the point across and only when it's called for. If you were to convert the example above to a story scene you'd only have to describe the subway (or whatever mode of transport you'd use in the future) and the device you receive the message on. Neither one of them needs a long description either, stick to the story and you're good to go.

Inventing time

Right, let's get into the inventing process of it all. It's tricky to create a realistic futuristic world when you have no idea what technology might be available at that time, but first and foremost remember that it's entirely up to you in most cases. It's your fictional story after all. But many will still want to go for some form of realism and there are plenty of readers who would expect the same, so let's delve into some guidelines you may wish to follow to try and predict what may be available in the future.

Technological goals

One easy way to predict the future is to simply look at what we're trying to achieve today. Here are a few examples:
- Robots/AI: Robots are getting more and more advanced each day. They way they talk, the way they walk, the way they think and the way they learn. Everything's getting more advanced by the day, so all you'd have to do is continue that line and you end up with realistic futuristic robots in no time.
- Computers: Computers are getting smaller and smaller and more and more connected. I'm not just talking about personal computers or cellphones, but all sorts of computers. We're already capable of inserting computerized technology in our bodies to some degree, this'll only become more advanced in the future.
- Lab grown organs/meat/etc.: We're well on our way to create organs and other living tissues in laboratories. Your futuristic character will probably have access to relatively easy to come by replacements for any body part that may get permanently damaged.
- Virtual reality (VR): We're still very much in the baby faces of VR, but the progress that's been made and is continuing to be made every day is tremendous.
- Anti-aging/medicine/etc.: We're learning more and more about how our own bodies work and how bodies of other animals work. We're able to genetically modify all sorts of creatures already and we've even managed to clone animals. The next few steps are obvious and probably inevitable. Many diseases and other problems of today also won't be as big of a problem in the future. At least, let's hope so. New ones will probably pop up though.

As you can see it's easy to continue down the lines of what we're trying to do and simply making those things available in a futuristic setting. But if your story is set far enough into the future you'll have to add more onto these goals. The trick is to simply think of what would or could come next. What would come after robots/AI? How about improving our own capabilities or how about robot and human relationships?
What comes after lab grown organs? How about the ability to simply regrow them yourself (regeneration) or the ability to replace your own parts with superior lab-grown ones?

If you're having trouble thinking this far down the line of what we might achieve don't worry. First consider what you need in your story. Does your character need to be able to survive a fall that shatters their legs to the point that they can keep going soon after the fall? Well, let's think. Could the legs be repaired within a week with advanced medical procedures? "No, that's too advanced, my story isn't set that far in the future." Okay, what about 'simply' encasing the upper and lower legs to let them heal, while letting a robotic exo-skeleton do all the lifting and walking for the character? Exo-skeletons are already available today, your futuristic characters will no doubt have access to them. The healing part gets a little trickier to deal with from a realism point of view, but as long as it's feasible you're usually good to go.
A big part of all this is problem solution, but you create the problems yourself. This doesn't always make it easier to find a solution, but you could always change the problem if needed.

Outside the box

Thinking outside the box is tricky if you're not used to it, but it is a great tool to help you come up with futuristic technologies. Many futuristic stories follow the same tropes, some might even call them cliches, when it comes to technologies available in their story universe. Robotic servants, often with some form of AI, is one of those. Of course, robotic servants is something we're working on right now and already exists to some degree, so while it may be overdone in some settings it definitely isn't an unrealistic idea.
But by thinking outside the box a little you can often come up with some uses for futuristic technology that works of fiction cover less often. Of course, virtually all ideas have been done already so no matter how far outside of the box you think you'll likely end up with something that has been done before.

But let's come up with some examples of thinking outside the box and let's go with the robotic servants/AI idea. Robotic butlers is fun and all, but there are far more practical and life improving things a robot could be used for. Plus, realistically speaking a robot servant would be very expensive.
Emergency response would be something robots would be incredibly helpful with. If every building had a robot ready to respond to an emergency call the time it'd take for help to arrive would be cut down significantly. The further set in the future the better the aid the robot could provide. Stabilize wounds, capture a thief, break up a fight or just simply helping an elderly person who has fallen down back up on their feet.

Another exploitable area would be uninhabitable places. Robots could easily work in areas humans would simply not last for too long. Radioactive areas, war zones, excessive heat/cold or even uninhabitable planets. In some cases robots are already used for this today, like in war zones. But if you take it a step further and insert AI in these examples you could end up with societies of robots. Small towns, large cities or even entire planets completely inhabited by robots.

So what do these examples have in common? They took existing ideas, but applied them to different uses and in doing so made them a little more 'original'. Does this mean they're better? Not necessarily. If your story requires people to have a robotic servant there's probably no point in having emergency standby robots as well, at least not unless those robotic servants are incapable of performing these first aid tasks. Unless those robotic servants are the ones humans may need saving from (dun dun duun!).
The point is to look for other uses, which is made easier by simply looking for problems in real life. Emergency response is a problem and so are uninhabitable areas, so the logical step is using technology to solve those problems and in this case it was done with robots.

Money, money, money

If there's one thing that drives development it's definitely money. If you're unsure whether or not your invention would realistically be part of life in your story universe consider whether or not somebody could've made a lot of money with it. This does mean ignoring flukes for inventions or other creations that shouldn't have made the inventor money, like a pet rock, but inventions that people would actually use and could be made at a cost that would bring enough money at a low enough risk. This doesn't mean flukes never happen, they do, but it can come across as gimmicky and unrealistic, especially when used too often.

Let's illustrate this with an example: A company has the choice of investing in contact lens technology that allows you to see a wide range of information right there on the lens or the company could invest in ear pieces that enhance your hearing and allow you to hear whole new frequencies of sound. Which choice would the company go with? Clearly the first as there's way more money to be made there. People aren't really that interested in hearing new frequencies, but people are definitely interested in being able to see information on a lens on their eye, especially considering this promises for far more advancements in their future.

But what if you need that hearing enhancement to be part of your story? Well, simply make it happen. There are several ways you can go about this without making it unrealistic. Devices for the hearing impaired are always something that could make a company money, not a whole lot, but enough for investors to invest at least some money. This development could lead to technologies that could (and hopefully would) be used by everybody and suddenly there's a bigger potential market and thus more money.
Alternatively a whole lot of discoveries are done in the name of space exploration, war and other fields of life most people don't consider, at least not as far as new technological discoveries go. Enhanced hearing may be a vital necessity to fight an enemy during a war or to listen for very specific sounds in space (not necessarily by humans) and these solutions could translate to devices we use in every day life. These kind of discoveries are something that has happened and continues to happen a lot in real life.

Of course not every device in your story needs a realistic backstory, some can simply exist. But if you do need a realistic backstory at least now you have some ideas of how to go about making this happen. There's plenty of ways to make something appear realistic, even if you have to go about it in an indirect way at times.

Competition

If there's one thing that drives technological advancement it's competition. Competition comes in many forms of course. There's competing companies striving to outdo the other and thus outsell the other, there's competing nations trying to be better than the other (and race to the moon), there's war in which it is absolutely necessary to outdo your competition and then there's things like disease that may require an immediate solution or risk losing everything.

A perk of this is that it offers an easy explanation for any technology in your story universe that may be ahead of others. Of course don't overdo it as that would make it unrealistic again. Advancements in one field often lead to advancements in other fields as well, so while you may explain advanced spaceships through some form of competition this usually also means other forms of transportation and anything else that comes with or is related to spaceships has advanced as well.

A real life example of technological advancement made during World War II is the pressurized cabin. Without pressurized cabins flying at high altitudes comes with all sorts of problems, both in terms of comfort and in terms of health risks. The initial solution was oxygen masks, but those offer only minimal freedom of movement and only help for as long as they work (they failed fairly often). Jet powered aircraft were also an area a lot of manpower was spend on as it'd mean air superiority.
Today millions of people fly in a jet powered aircraft with a pressurized cabin every single day. This is something that would've happened eventually even if World War II didn't happen, but World War II definitely sped up the advancements. Then there's things like the microwave. It was created with and discovered through radar technologies which were created during World War II (there's more to this, but let's not delve into the discovery of the microwave here).

Efficiency

This ties in with the previous points as efficiency tends to lead to a potential for more money, a potential to outdo your competition and so on, but efficiency is definitely something that drives technological advancement. In some cases it's because the current stage is not good enough (like many robots today), in other cases it's because more efficient means it'll be more widely available and in other cases it could mean a bigger improvement on life.
So the main point to take away from this is to consider whether your invention is more efficient than what was available before it. For example hover cars (and flying cars) are not more efficient than regular cars. At least not in most of the forms you see in works of fiction. Consider the following: What would happen if all the terrible drivers we have today (and there are plenty) suddenly have access to a third dimension? Not to mention the logistics and costs involved of implementing an infrastructure that supports new vehicles. That doesn't mean it's completely out of the realms of possibilities though, so don't feel like you can't add them at all. Just make sure you think about it a little if you're going for realism.

Expanding ideas

So by now you hopefully have at least a decent idea of how to make your technology fit within your story universe, but there are a few more things you may wish to keep in consideration both in terms of story telling and in terms of realism. Depending on the story you're writing not all of the following points will be all that important or relevant, but in most cases they're at least worth thinking about.

Normal

One thing to keep in mind when creating technology and whether or not to describe it in full detail is whether or not the technology is considered to be normal day-to-day technology or cutting edge technology. If you were on that same subway from earlier and saw somebody with the latest smartwatch, a bendable tablet, a mini drone or a portable VR set would you be surprised? Would you care enough to notice and remember it? In some cases the answer would be no and in others it'd be yes and the same would likely go for your characters and whatever technology they come across on a daily basis. If the technology is pretty mundane there's no point in mentioning it, unless it is relevant to the plot. Of course there's no point in mentioning non-mundane technology either if it's irrelevant to the plot, but non-mundane technology is noticed faster and thus potentially easier to interweave in a story.
Sure, describing that somebody on that subway has an artificial arm which can produce a hologram on the palm of their hand with which they are communicating to somebody else definitely makes it clear what kind of technology is available in this story universe, but if this arm/hologram technology is never used in the story it doesn't add anything to the story and thus can and should be left out.

Effects

Something else to think about is what the effects of your technology are on the daily life of people. An obvious real life example is how cellphones allow us to always be in contact with other people. If we're late for something we can usually let the other party now, but the effects you may want to think about go beyond these obvious things as well. Let's say that flying cars are feasible and a reality within a story universe, what effects would this have on the daily life of people? Less traffic jams probably, since there's a new dimension to work with so you'd end up with stacked lanes. But if an accident happened on the top lane they'd crash onto the bottom lane and cause a way bigger accident, not to mention the fact they may plummet from great heights and increase the risk of death for whoever is in the flying car.
What about licenses? Would a driver's license be sufficient or would you need a pilot license? Does this mean a new minimum age? Stricter rules? Or are all flying cars simply automated?
Travel time would probably be shortened, but flying cars would likely be more expensive than regular cars. What about a police chase? That'd be far more dangerous and far more difficult, so as far crime stories go a flying car would up the stakes.

As you can see there's a whole lot to consider whenever implementing new technology, but don't worry as most effects may be completely irrelevant to a story and thus not worth mentioning. It's still fun to think about though and it helps make the world more realistic to yourself and this in turn may help with the writing process. But it does bring me to my next point.

Plot holes

An important thing to think about is whether or not the technology in your story universe could resolve part of your story in a better way than what you're writing or whether it creates some gaps in logic in your story. Time travel is one that rarely gets away with it, but it can happen with any kind of technology. Of course, if you are facing a plot hole it doesn't mean you have to get rid of either the technology or the way you want things to resolve. You could simply add elements that'll make the plot hole mute. Let's say lab grown organs and other living tissues are a reality and very common in your story universe, but you still want your character to have to deal with a serious injury for a while. Well, health insurance could still be a thing. But what if everybody has access to health care and money and such is no issue? Well, your character could simply be against lab grown organs from a moral stand point, your character could have a body that rejects all lab grown tissues (maybe the techniques haven't been perfected yet) or there could be a waiting list to deal with and your character is not exactly a priority due to life choices they make (similar to the current donor lists).

Suspense

Besides the effects of technology on the people in your story and whether or not it could cause plot holes you may also want to think about the effects it'll have on the story itself. As technology evolves and makes our lives better, safer and more efficient it also potentially takes away the suspense you'd otherwise find in a story. Injuries we face today may have meant death a few hundred years ago and may be no problem whatsoever a few hundred years into the future. Losing a job could be an absolute disaster today, but in a future where robots do everything there may be no jobs to lose. A house fire could mean the loss of all sorts of precious items, like photos and gifts, but in a future where everything is digital and/or 3D printed the sentimental value may be much lower.

While these effects are often fairly minimal it is something worth thinking about. Adding that special gadget could just mean you might miss out on a great emotional moment for the reader later down the line. Of course at the same time adding new gadgets could mean a whole new range of problems and potential moments of suspension are added as well, like the potential for memories to be selectively removed for example.

Final note (faking it)

Hopefully you have a pretty good idea of how to create realistic technology for your story universe by now, but there's one final thing you can do and that is simply faking realism. If something works in your story universe and if it comes across as realistic within that universe you're most likely going to get away with it. Light sabers, time travel, faster than (or close to) the speed of light travel, human teleportation and many other popular fictional technologies are either impossible or very improbable in real life, but they're common technologies we accept in science fiction. Part of why we accept them is simply suspension of disbelief (and perhaps a little ignorance), so as long as you can make your technology seem realistic within your story universe it likely doesn't matter too much whether it really is or isn't. Whether you get away with it or not depends on what kind of story you're writing, on the story universe and on your own writing ability.