Seth Godin always has interesting points to make. In a recent blog post, he made the following point, one that I've been trying to get through to people for a very long time:
"The art of marketing is not finding more money to do more marketing. It's figuring out how to tell a story that spreads with the resources you've got."
So many self-publishers and new authors want to throw money at marketing or hire someone else to do the marketing for them when they should be spending the time creating great stories. By great stories, I mean, marketing messages that move people, get people talking, get people telling others about your story, etc.
Before you do anything else to market your book, decide what your story is -- what message will move people to act.