A list I compiled after reading my screenwriting class' assignments, which was to write a one minute screenplay that tells a story but doesn't use dialogue. Not in any order of importance and some of this is probably self-evident, but it doesn't hurt to be reminded:
1. Miming is not visual storytelling. Visual storytelling means figuring out HOW to tell a story using images, not just removing dialogue.
2. Real time is not the only possible time in film. Screenwriters can use the power of edits to tell story instead of everything happening in a continuous real time.
3. Avoid describing action in a sentence, that could take a few seconds on screen. You need to figure out how to lay out a scene on the page so that the page length matches 1 page/minute of screen time.
4. Remember each scene must stand on its own for production. Don’t need something in a scene you don’t make explicit reference to in the scene.
5. If something can be misinterpreted, it will be.
6. Location and int or ext depends on where you want the camera. Eg. An EXT scene with a tree with a bird in it, but seen from someone inside’s POV, would really be INT. Seen through the window…
7. Most stories lack conflict and rising action because of a passive hero. Need to see hero struggle. Need to FORCE character into action quickly.
8. AVOID PASSIVE VOICE
9. You need to make your script a good read. Be vivid, not technical in describing what we see.
10. Avoid paragraphs longer than 4 lines. Keep each paragraph only as long as a shot, both in length and content. Even if you think it will be one continuous shot, don’t make it hard on reader. Use lots of white space on the page.
11. Don’t use scene numbers until script is in production.
12. Unless there’s some important reason not to, NAME your characters.