I'm writing a story set about 50 years from now. It's not really a sci-fi story with wild imaginings of the future. It's just some sort of action story that takes place in a future setting. And so far I've alluded to a few things in what I've written at this point, but it doesn't stand out that much (which is kind of what I'm going for). But when using a futuristic setting, how much will people typically expect you to really go into the technological / sociological aspects of a future society?
Enough to make the core logic of the story functional. In theory, the emotions, motivations, and driving engine (save the world, get the girl, rescue the kid, catch the killer) need little explanation. But also, in theory, there would be no need to set the story fifty years in the future if that was all you wanted to write about, so the reason for that setting would also have to be logical. I'd say do enough to justify the futuristic setting. There has to be a reason, right? Figure out what that is and use it to blend and contour the technology and mindset into the more familiar core of the story. If it's just new gadgets and shit that should be pretty easy to do since the reader will already be looking for it. And the more familiar and simple the plot, the more the props will stand on their own and won't need a lot of explanation anyway.
I would agree with sentiment. Yes world building is important but the need to explain everything doesn't justify the setting. Leave some things open to interpretation. Characters come first before setting does.
Don't explain anything that doesn't need explained. Exposition for the sake of worldbuilding kills. Nobody cares about how much detail you put into creating the world if it doesn't effect the main character, and even then sometimes its best to just not explain it. You may or may not be surprised at how much people take for granted in stories without questioning them.
I'd suggest focusing on what the character, not the reader, cares about. If you need the reader to know something, then make it something of immediate importance to the character, too. For example, if you need the reader to know that there are severe food shortages and that food is used as a way to control the population, then threaten the character's food supply. If you need the reader to know that water is scarce and expensive, make it important for the character to bathe for a critical occasion. And so on.
Think about it this way. Remember the movie Blade Runner? The original one, not the sequel (nothing against the sequel, just I haven't seen it yet, so it may or may not be relevant.) It's set in the future, 20 or 50 years or so. What do we know about that future? 1. There's a lot of pollution 2. Real animals are almost extinct. 3. There are artificial people and animals (replicants). 4. Replicants aren't allowed on Earth. 5. There's a war offworld, being fought by replicants. So that's what's relevant to the story about this future. What don't we know? (forgive me if some of these have been answered, my memory is a little fuzzy*) 1. How long have the replicants been around? 2. What were the early versions like? 3. What debates took place at the various stages of their development? 4. Who or what are they fighting? 5. How are they fighting? ("attack ships on fire") 6. Why aren't they allowed on Earth? There's a lot of the Blade Runner world that's not shown to us because, for this chapter at least, it doesn't need to be. Your story only needs to build the world that the characters interact with, the rest can be implied in broad strokes (although it's good for the author to know the answers, even if they never appear on the page). Spoiler: *my memory
To expand on what the others have said, a setting has "character" because of the "characters" that live in it and breath that life into it. As long as you make the details of your setting relevant or impactful to the character, than those same details will become relevant or impactful to the reader. I can see a beautiful, high resolution picture of the Grand Canyon (in the US), but it wouldn't have the same effect on me as it would if I were actually at the Grand Canyon. When your character is gazing out upon a dense and futuristic cityscape, it is the character's impression or opinion of the city that truly makes us interested, because those impressions give the city color (or lack thereof) and personality. It's the same with the conditions and circumstances in that environment. You can tell the reader that the city suffers from a shortage of water or food (as jannert gave an example of), but it's when you show the main character's siblings or parents emaciated from hunger and thirst, with the main character scrounging for the coin to save them, that you attach meaning to the state of affairs in the world you build. It's just as in real life, as unfortunate as it may be. You will hear about people starving in third-world countries, and think it's sad, but the reality only hits you if you get fired and end up living on the streets scrounging for food, or if you go to those countries and meet face-to-face those poor children who are nothing but skin and bone. It is a character that connects emotion and understanding to the world you create.
For doing a story so close to our timeline a LOT of research needs to be done. Looking into Global Warming and how that will effect us in 50 years (Much more wild fires and freak storms) and how we will adapt to that. General technological adaptations in 1st world countries and how whatever country you are placing this in has changed. To put is simply you must look into problems we have today and theorize (and look at theories) of what yesteryear will bring. Which is a lot more research to be done than saying "Spaceships work like this generic already put forward theory that everyone knows already".
I'm personally a HUGE fan of exposition through dialogue. Depending on the sort of world you're building for your plot to take place, having characters discuss the world around them in a similar manner to how real people talk about the real world around them is a great way to do things, in my opinion. It keeps you from info dumping your audience because the characters involved in the discussion already know a great bit by nature of it being their home world. There's also the advantage that it can blend into the established pacing very smoothly because it'll only come up when it's relevant enough to come up. A good way to dump a lot of information at a time would then be to have two or more characters get into a heated argument about the status quo.
This could be a really fun thing to try and predict for ourself what the world is going to be like then, but what do you need to know? Weather is important for settings. So how will this be different in the future? Buildings are getting taller and leaner all the time. Where will your main character live or work? How many people are there? Has overcrowding got really bad? Or has it gone the other way? Perhaps allude to last events (between now and your future) and hunt to their outcome. The less world building, the more fluid the story. Add to your world as time goes on, but through the character’s eyes.
I would suggest that you write you story draft, just put it on paper as it flows from your imagination. Then, break that story draft into a scene list, or some sort of outline. From this outline, you should identify the elements of your world that you will need to develop. Think of your world as another character in your story and develop it according to its role. Godspeed!
Because it's 50 years in the future of the modern world, a lot of worldbuilding is going to be done for you. Foods don't change too much, many locations and buildings are the same. The reader is allowed to presume consistency with anything you don't mention. Since this isn't a fantasy for far-future setting, this is perfectly okay, but it does leave a lot up to mystery. I would define a few very specific things in your story, and build from there. A few things that are quite different are going to be intrinsic to your character's life, and things you can lightly touch on, "I picked up my wash-sponge and waterless-soap to clean myself with" to hint at a world-wide or at least local drought. Your character won't care as much because it's everyday life, but it is still important to give your reader an idea about what kind of crisis the world is or is not going through, allowing them to build their own framework of a world. Dropping hints like this can be very influential at getting your reader intrigued; the idea of the existence of the Koloss from Brandon Sanderson's Mistborn series comes to mind; they mention them as being fierce warriors and under the control of the Lord Ruler, as an overarching potential threat, but in the first book you know nothing else. It hints that there is some larger, expansive world out there. Bring in an artifact from this larger expansive world. Some little detail, something otherwise inane and pointless that makes your reader assume you've got everything else planned out, so anything you introduce later is "oh, of course, I should have realized they'd have that," as opposed to the reader just rolling their eyes at a Deus Ex Machina.
I would say enough for there to be a noticeable change in the world between now and your future setting. It doesn't have to be technology either, it could be political ideologies or cultural differences. Right now I'm chipping away at a big project which covers future history from the 2020s to the 2080s or so. The biggest event in my series is a global war in 2045 which leaves most nations in complete anarchy, with a small group of other regions remaining in their own stable bubbles. In terms of technology, the war has drastically slowed down technological progress. The only major technological innovation is that humans have been able to convert raw energy into matter, which allows a select few nations to supply their citizens with enough food and shelter to remain stable. I'm still working on the details of this technology, including some limitations because I don't want it to end up being a 'give infinite items' cheat code. But mostly the technology isn't the focus of my future setting. It's the aftermath of the war and the new political situations that result from it.
