David Fuller, author of "Sweetsmoke" left this as a comment on the Royalty Free Fiction blog.
"I have a theory with which most teachers of writing disagree. I believe you should write what you don't know. I believe you should do research and learn about other things. Then, when you write, you come into the equation and fill up the work, as it emerges through your own prism. So there it is: Write what you don't know."
I thought this was a great tip, as it is often the way I work. In historical fiction, I often find new aspects to the story this way, and it also keeps my mind fresh and interested. And David, I couldn't have put it better myself.