Well, a few months ago I met a fairly well-established author. When we were sitting at a table together, I told her I was working on a book. I said I wasn't sure about getting it pulled together and all she said to me was: "Just write." And that is the gist of it. If you want to write a book, write it. Don't worry about timelines, index cards, entire plots and all that. I'm sure I'll get some flak for that, but that is how I write. I jot down my notes as the words flow and I just write. Many times I'd go to bed thinking about the next chapter, and it would all completely change the next morning! At some point, you have to let the words lead you. You'll be surprised where they take you. I certainly was!