When I wrote my first two short stories, I just wrote… let the story take off running and see where it led me. I had a good idea what general direction each was going, but as far as the destination… no idea. The third short was a bit more directed… I had a direction and an ending, but the path to get there could be as meandering as it wanted to be. My Nano novel started like that. I had a beginning (pretty much the first four chapters already written), a middle (kinda), and an end (which changed a little bit, but was damn close to the original.)