No one cares about your book as much as you do: not your spouse, not your publicist, nor your mother, and certainly not your publisher. You must become the champion of your book.
Take Seth Godin's Advice for authors to heart, especially:
7. Think really hard before you spend a year trying to please one person in New York to get your book published by a 'real' publisher. You give up a lot of time. You give up a lot of the upside. You give up control over what your book reads like and feels like and how it's promoted. Of course, a contract from Knopf and a seat on Jon Stewart's couch are great things, but so is being the Queen of England. That doesn't mean it's going to happen to you. Far more likely is that you discover how to efficiently publish (either electronically or using POD or a small run press) a brilliant book that spreads like wildfire among a select group of people.Great advice. If you follow it, you will be a happily published author, not a bitter one, wondering "what the heck happened?" three years after your book comes out.
What do I mean by "champion"? Seth nails it here: "a non-fiction book is a souvenir, just a vessel for the ideas themselves. You don't want the ideas to get stuck in the book... you want them to spread."
Similarly, if your book is a novel, realize that a novel is just a container for an experience. Who will the experience of your novel help, intrigue, entertain, amuse? When you know that you're creating experiences when you write novels, it makes your novels both easier to write and to champion.