This may sound obvious and stupid, but if I had a bus token for every wannabe manuscript I've read that starts before the beginning, I'd be crossing the Panama Canal right about now. I don't care what your character had for breakfast. The key is to make your first sentence of your first page–if possible–encapsulate the beginning of the
"problem." One of my favorites is the opening line from Frederick Forsyth's THE FIST OF GOD: