For those who don't know, a reader is the first line of defense a studio or production company has against unsolicited screenplays. Often a college student, the reader is commonly characterized as a creatively bankrupt imbecile whose job it is to keep wonderful screenplays from getting into the hands of those powerful people who would surely buy them if they had the chance. Why, you could go years without reading a good rattlesnake farm scene, and here I had three in one week. And as a reader, you quickly recognize some key patterns. Like all scripts with fancy covers are bad.
Scripts submitted by agents are at least well-written.
And please, don't begin with your lead character waking up in the morning after a pan of the junk in his room. It's by far the most commonly chosen opening. For my coverages, I referred to a checklist of basic 'rules' provided by a small production company. Over the months, I added to it and revised it quite a bit, combining it with stuff I'd read, and with guidelines provided by other companies. I even gave a copy to my story editor when I left my last job.