Short stories generally do not require as much worldbuilding as novels.
That may seem an obvious thing to say, but it’s something I sometimes struggle with when I’m writing fantasy or science-fiction short stories. Unless I set a short story in a universe I have written in before, it means coming up with a new world to write in. I try not to do a whole lot. Whereas with a novel I might map out the history of the world (to varying depths depending on the needs of the story, of course), with a short story I will stick strictly to what I need and never make notes on it, again unless it happens to be set in a world I’ve already written in before.
Still, despite that, writing short stories can be difficult for me because I run into a couple of temptations.
The first is to expand the short story into a full-length novel. This isn’t an entirely bad thing to happen, mind you, but I don’t always want to write a novel because I’m not always interested in fleshing out a world or universe in immense detail. Sometimes I just want to explore a simple idea, without having to commit to the length of time a novel usually requires.
The other temptation is to not use any of my good ideas. This thought stems from my fear that I might “waste” a really good idea that I could use for a novel later on, but it’s a really silly fear when you think about it. I don’t believe there is such a thing as a “wasted” idea. After all, there’s nothing stopping me from taking that same idea later on and expanding upon it in greater detail in a novel.
Nonetheless, every time I sit down to write a speculative fiction short story set in a universe I’ve never written before, I feel like I have to do the same amount of worldbuilding I would do for a novel. This is where I am thankful for the Ambage, my writers’ group. For both of the anthologies that I’ve contributed to so far — Constellations and Fantastic Depths — I’ve forced myself just to write my stories and do only as much worldbuilding as each story requires, no more, no less.
Once I get past this irrational desire to worldbuild in excess, however, short stories are usually great fun for me to write. Not quite as fun as novels, true, but they are still fun, as writing should be.