You just kind of have faith. If that sounds kind of mystical, it`s because I really don`t know how it works, but I trust that it does. I try to write the way I read, in order to find out what happens next.
You can be interested in a Jane Smiley novel whether or not anyone says a word. She enters into her characters` thoughts with great understanding and depth.
When I start getting close to the end of a novel, something registers in the back of my mind for the next novel, so that I usually don`t write, or take notes. And I certainly don`t begin. I just allow things to percolate for a while.
When I look back over my novels what I find is that when I think I`m finished with a theme, I`m generally not. And usually themes will recur from novel to novel in odd, new guises.