16. Your Secondary Characters Are Way More Interesting Than Your Protagonist
It's all right: even the professionals get this wrong from time to time (J.K. Rowling, we're looking at you), but if you've never had a screenplay produced before, Hollywood is going to a whole lot less forgiving when it comes to this factor. So try and make sure that your protagonist is, generally speaking, as interesting as all those crazy secondary characters you brained up so good.
15. Your Screenplay Is Too Long
Seriously. We don't even have to read your screenplay to know that it's too long. First screenplays always are. Go at the damn thing with a chainsaw, cutting away anything and everything that isn't entirely necessary to you story. Be merciless, because agents certainly will be when they realise your 90 page script is running at 156 pages and they've run out of toilet paper.