A few days ago I was chatting with a fellow with a long background in "the biz" who had recently shifted more into the writing arena. He was having trouble getting going on a project and asked for my advice.
Mistake number one is asking ME for advice. There's a reason the Wikipedia entry on "well adjusted movie and TV writers" is blank... we're all a swirl of mixed emotions, self-doubt, casual/cocky self-assuredness mixed with grim dark nights of the soul. Anyone who says different is lying. And if they're not lying, I hate them.
(Note: this is not whining. Writing for a living definitely beats spreading asphalt, working at McDonalds and fixing copying machines, just three of my pre-writing jobs. I fully appreciate how fortunate I am to have actually managed a career in this insane field. Though I did get all the free hamburgers I could eat when I was working at Macs...)
Anyhow, my advice to my friend was pretty simple. Just start. Sit in front of the computer, type the title and then write something, anything to get the ball rolling. Fully understanding that those first words will probably never make it to the final script, let alone to the screen.
Breaking the ice is always the hardest, and it doesn't get any easier even after many years and many scripts. In fact it may get a little harder, because if experience teaches anything, it's that writing this stuff is hard. So you're not just looking at the project when you're starting, but you have a full understanding of the amount of thought and butt-in-the-office-chair time it's going to take to finish something worth reading. The trick is to STOP thinking about that and just keep going...
And if you can't get started, you can always kick-start the process by writing on your blog, he said optimistically...