The (London) Times had an interesting feature the other day on writing films. Several top writers revealed their writing process and one of the most interesting was Lee Hall, writer of Billy Elliot. Here's are the highlights of his process:
"I start writing by dreaming up the story first in images. With Billy Elliot I saw a kid from a pit village jumping on a bed--what I used to do in my granddad's house--but he was wearing a tutu. ...
"Next I normally make some notes and then take a huge piece of paper and free-associate what the essential scenes will be...and then I draw lines between the different scenes and plot how they will connect up.
"Then I write the first draft; this doesn't take long, about ten days...I write a prose description of each scene on little cards: how will it look, what are the central arguments or developments within it? Is the sequence of scenes making sense? I do it in chunks but try not to imagine the whole thing too much. If you do, there's no room to breathe, or to have 'accidents'...
"I never look back while writing the draft, I get too depressed at the gap between my aspiration and the outcome. .. At the end you go back and go through it and through it and through it again."
(There are useful tips about screenwriting in my book, "Your Writing Coach" and the www.timetowrite.com website.)