Ask yourself these questions about a recent piece of your work:
- Does it happen in as short a time as possible?
- Does it happen in one place or as few places as possible?
- Do I use only as many characters as are strictly necessary?
- Do I only include an action or detail if it's vital to the plot?* If I have subplots, do they all significantly contribute to the main plot?
*Chekhov's Gun: Don't put a loaded gun on the stage if nobody is going to fire it.