I have been a skimmer all my life.
In other words, my "eye sweep" collects sentences in one big swoop, i.e., gathers large phrases from left to right. Essentially I read down the page in a vertical fashion.
You should know this because this is how a reader reads. He/she is reading vertically to get through a script quickly. Anything you can do to help him/her is a plus in your favor.
Here are the things that delay my vertical reading:
- long narratives
- paragraph-y dialogue (more than 2 lines)
- looooong sentences
- choppy sentences that require me to stop-start-stop-start
- TOO MUCH BLACK INK ON A PAGE (not enough white space)
- TOO MUCH DETAIL
- too many parentheses
- pages and pages of dialogue without a break (this indicates that dialogue is trying to carry your story)
WHAT I'VE LEARNED: When you're evaluating your script for ease of reading, time someone else reading it to see how fast it takes.
If you can do it without them noticing, watch their eyes. Do they have to go back a lot & re-read certain passages? That's probably b/c you weren't clear enough the first time.
Scripts that physically have lots of white space immediately put me in a good mood. "A-ha!" I think, "the writer gets that economy of words is important!"