As most of my writing seems to lean towards the sci-fi/fantasy genre (both when involving smut and not involving smut), one thing I've been trying to educate myself about is "world building". If the story's not taking place on Earth, with humans, in the past or the present, time and energy needs to devoted to setting, cultures, traditions, and overall, the "rules" of the fictional universe. Those rules help form the structure around which everything else will take place.
For those with wild imaginations, coming up with the ideas is not the difficult part. The challenge is finding a way to convey allllll of that information that originally exists only inside the writer's head in a way that is entertaining and engaging (and makes sense). No one wants to be guilty of "info dumps" or "As you know, Bob" dialogue, and readers don't want to read it, either.
So how do we set our scenes, describe every detail of our fantastical worlds in a way that will capture our readers and immerse them in our fiction? The approach I've decided to take is to almost treat my writing as non-fiction based on ideas that people already know. If I act like my ideas are completely new and different, I think it actually causes the opposite of the intended effect in that it takes the reader out of the story, rather than drawing them in. The characters shouldn't behave like anything is out of the ordinary if, initially, nothing is out of the ordinary. Establishing scenes don't have to be very long. I think it's far more effective to gradually reveal key information as the story naturally progresses, rather than flinging it all in the reader's face at the onset. The story should grow organically regardless of the setting, and nothing should feel unnecessary or forced.
Or, to summarize: don't treat your readers like idiots. Even if you've come up with a super complex world in which gravity works completely differently, or women wearing yellow hats is a sign of war, or people communicate across millions of miles using microchips implanted in their toenails, assume that the reader will be able to catch on to these concepts quickly without have every single nuance spelled out for them. And even if they don't, there's fun to be had in the journey.