Having taken a cue from Billy Mays, I decided my best bet for marketing is to yell at everyone at the top of my lungs. Ready?
MY BOOK IS AMAZING! YOU CAN GET IT FREE IF YOU CALL IN THE NEXT TEN SECONDS with the exception of shipping and handling which comes to 22.95 plus tax to ship anywhere in the continental united states but not canada, europe, or anywhere else in the world. CALL IN THE NEXT TEN SECONDS TO TAKE ADVANTAGE OF THIS EXTRAORDINARY OPPORTUNITY TO PREORDER THE NEXT NATIONAL BESTSELLER!
Marketing is hard. It starts before you even finish the book. Okay, so maybe you actually should finish a draft of the book before you begin marketing it, but as an author your real merchandise is YOUR NAME. Sorry. Yelling again. Drat that Billy Mays.
My point is, even if you don't start marketing your book before you finish it, if you want increase your chances at publication, marketing your self, creating a ready-made following that a publishing house can work with, makes sense. Lots and lots of sense.