After working on a draft for a new book for three months, I felt a dull sensation that I'd merely written an interesting biography of a character. Here's her family. Here's her strange house. Here's what happened to her in the sixth grade with her science project partner. Those weren't wasted pages, but they didn't comprise a story either. It wasn't until I abandoned those 70 pages (Ouch!) and put the character in a dangerous situation that scared me on page 1, sentence 1 that an interesting story began to emerge.
So go write a sentence that scares you a little. There are so many possibilities.