I found this in Writer's Digest Online. It's from an interview with Anna Quindlen - a woman who has my dream job as a bi-weekly columnist for Newsweek, when she was a columnist for the New York Times she won a Pulitzer and she's also written several novels.
Anyway, here's the advice she had to give to other writers:
"It all comes down to the Nike slogan. Just do it. So many people tell me, well, I'm thinking of writing a book. Does anyone say I'm thinking of performing surgery, or I'm thinking of designing a building? Writing seems to be the only profession people imagine you can do by thinking about doing it. No. Put your butt in a chair and write. And never mind feeling blocked. Everyone feels blocked all the time. Madeline L'Engle (A Wrinkle in Time) once said, 'Inspiration usually comes during work, rather than before it.'"