Be prepared to work. As fun as it sounds to make your living in the land of make-believe (and it is,) there's a lot of hard work that goes into the process. Learn to love that more than any trappings of success that follow. You can't guarantee a bestseller. You can guarantee the best book you can possibly write. So put the book first. Work hard, polish and tinker. Present your best ideas in your best voice. Everything else will come when it's time. You'll still have to hustle, but it'll be worth every second.