Keep in mind that everyone who will ever read your work is always overworked and overwhelmed. So you need to give them the information they need to stay comfortable in the easiest way for them to get it.
Make it easy for them to understand what is in your head. Just because you know something doesn’t mean they’re going to get the same image, same action, same meaning from the dialogue that you do.
Imagine your reader, sitting down to read your work, totally exhausted. Not chipper and “first thing in the day” bright and perky.
If you make them work too hard to figure out what you’re telling them, they won’t get it…
For instance… Do not make them read dates and expect them to do math.
Your movie takes place in 1980. Dad left Mom in 1968 and daughter is getting married now. Dad comes back for the wedding. Is Daughter thirteen now? Forty? Don’t assume your reader can do math and read at the same time. You’re lucky they’re reading your work, so make it easy for them. Say, “Today is 1980.” Dad left Mom 12 years ago, when Sally was ten. Now she’s 22 and getting married.” So much simpler.
Be nice.
Do not tax the reader’s overtired brain for any reason. Just cause you know something doesn’t mean the reader can easily do the work required to gain that knowledge. Assume they’re very sleepy and everything is difficult for them to figure out.
Your Screenplay Sucks! 