There is no excuse for writer’s block. If you’re stuck on one project, work on another.
If you find a word in a thesaurus, look the word up in the dictionary to ensure it means what you want it to mean.
Keep everything you write. I used certain lines from an essay outline to write a poem on short notice for a contest.
People aren’t always what they seem. Multilayered characters that keep you guessing are the most interesting but don’t use the first chapter as an information dump.
If it seems like you have too much dialogue or narration in your short story, it helps to create a visual: I highlight all the dialogue/narration in mine and look at my story from a multi-page view. This helps me know where to break up the narration with a scene.
Avoid phrases like “he jumped in the shower” or “she hopped in the car.” People don’t jump in showers or hop in cars. Use “he got in/she got in.” The former is hyperbole and doesn’t read well.
Never use cliches. If a character in your story is prone to them, put a new twist on an old phrase to freshen it up (unless you’re writing about a real person). If you can make the cliche humorous, even better.
Make your title memorable, but don’t use too many complicated or unusual names in a story. It comes off as amateurish.
If you’re going to emphasize a seemingly insignificant detail at the beginning of your story, that detail should play a role in the end.
If you use a semicolon to separate two sentences, ensure the sentences relate to each other in some way.