Well, I always say that the two things I was most disastrous at in my life, being a teenager and being a wife, were the two things I really wound up cashing in on when I was writing fluffy magazine pieces.
I think people become consumed with selling a book when they need to be consumed with writing it.
I was very influenced by The Magic Mountain. It's a book that had a huge impact on me. I loved that as a shape for a novel: put a bunch of people in a beautiful place, give them all tuberculosis, make them all stay in a fur sleeping bag for several years and see what happens.
I don't write for an audience, I don't think whether my book will sell, I don't sell it before I finish writing it.
Write because you love the art and the discipline, not because you're looking to sell something.