Kurt Vonnegut wrote 100+ short stories.
In 1999, he revealed the secret to writing a good one.
Here are his 8 rules:
1. Don't waste your reader's time.
2. Give the reader a character to root for.
3. Every character should want something. Even if it's only a glass of water.
4. Every sentence must either reveal character or advance the action.
5. Start as close to the end as possible.
6. Be a sadist. Make awful things happen to your characters. Let readers see what they're made of.
7. Write to please just one person.
8. Give your readers as much information as possible as soon as possible.
Want to go deeper? There are 2 ways I can help you: