So I came up with another short story idea yesterday while watching TV--it didn't fall on my head quite as fully formed as the one the other day, so I think it could use more time rolling around in my head. The ending's a pretty basic, common twist, so the point of the story--the So What of it, as my first English professor used to say--has got to be what leads up to it. It's got to be the kind of ending that enriches what came before, rather than just (try to) give you a DUN DUN DUNNNN moment. So. I think that's going to take a while to develop.
It's all good, though, because the hardest thing for me is coming up with concepts. I'm much more interested in and work better with character, and could write shorter one-offs about established characters, but when you're writing just a stand-alone short story, you don't really have enough room to get really, really deep into that, so it's more the theme, the So What, that takes precedence. The idea, really. And that's hard for me, to come up with stand-alone concepts. I don't know.