Too irresistible to pass up:

http://valleywag.com/tech/silicon-valley-users-guide/how-to-coast-to-a-writing-career-319758.php

AVOID: Your idea for a book. You’ll devote two years of nights and weekends to it, cause your girlfriend to leave you, and for what? A $10,000 advance and a box of remaindered copies. Instead, review your friends’ books. You’ll make more cash than them and they’ll pick up the check.

h/t Dave Winer.