The best advice I can give on this is, once it's done, to put it away until you can read it with new eyes. Finish the short story, print it out, then put it in a drawer and write other things. When you're ready, pick it up and read it, as if you've never read it before. If there are things you aren't satisfied with as a reader, go in and fix them as a writer: that's revision.
Neil GaimanI've known ambitious people with no aptitude for the thing they did. Most of whom, rather terrifyingly, tended to succeed.
Neil GaimanWriter advice... Write. Finish things. Go for walks. Read a lot & outside your comfort zone. Stay interested. Daydream. Write.
Neil GaimanI noticed a long time ago that the Universe rewards belief systems. It doesn't really matter what you believe - it'll be there and waiting for you if you go and look for it. Decide the universe is, say, run by secret enormous teddy bears, and I can guarantee you'll immediately start running across evidence that this is true.
Neil Gaiman