Writer's Digest is an excellent source for writers (and an interesting read for anyone who'd like the inside scoop on some great authors). The January 2011 issue is no exception.
I was especially taken with their interview with Harlan Coben, whom I consider one of the half-dozen best writers of thrillers alive today. I love it that he admits that sometimes even after the book ends he may not be able to decide who is the good guy and who the bad one. My own characters take shape as I write (without benefit of outline or preconceived notion), and they often surprise me as the book ends, making me go back and tweak some sections to fit the true personality they reveal to me by then.
Coben closes the interview with a comment that every writer should have posted in large letters above his/her computer: Amateurs wait for the muse to arrive; the rest of us just get to work. There, in a nutshell, is what often separates the wannabe writer from the serious one.
Since I see no sign of a muse, I guess it's time for me to sign off and begin writing. Have a great day.