Some nice advice from Steven Galloway in this Globe & Mail article:
Steven Galloway has achieved remarkable success by ignoring a piece of advice frequently offered to young writers: Write what you know.
"I believe that to be the biggest crock of garbage about writing I've ever heard," Galloway said recently over coffee in Vancouver. "I write what I want to know."
I can get behind that. It rings true to me. In fact, when I read it, it felt like such a relief, as though someone had just granted me permission to write with freedom. I write fantasy and may try my hand at science fiction. How could I possibly write what I know?