Check out the full article here: https://www.outstandingscreenplays.com/post/10-tips-to-make-your-short-script-contest-ready
But to cut a long story short...
1. Hook: Grabbing the reader on page-one is a must have.
2. Minimize Setup: The reader (and the audience) want to get to the good stuff quickly, so double-check that you’re only delivering absolutely necessary info in those all-important first few pages.
3. Make every line count: If something isn’t advancing the plot, giving essential exposition, expressing character, or is highly entertaining/engaging, there’s every chance it can be cut.
4. Shorter is better: Being able to condense story is a skill that will impress potential collaborators, producers, and studios, so it’s one well worth practicing.
5. Cut the fluff: Time is money, so script readers don’t want to spend time trawling through extra words that aren’t needed, which also slows the pace of the story too.
6. Show, don’t tell:A picture paints a thousand words, right, so scan your script looking for instances where a reaction, an action, or even a silence could be used to communicate the meaning of a line instead.
7. Foreshadow: Readers absolutely love setups and payoffs. They’re like mini rewards for paying attention.
8. Budget Check: Writing to a budget isn’t a restriction, it can actually help you find inventive solutions, so get creative.
9. End with a bang: When it comes to shorts, last impressions count and endings really need to create a long-lasting impact.
10. Polish, polish, and more polish: If your script is going to compete (and yes, repped writers also enter script contests), the formatting needs to be on point, the prose needs to be engaging and evocative, and the writing needs to be lean.