I think one of the most difficult things about being an unpublished writer is deciding what to write. After all, it takes time to write a novel, and you don't want to write yourself out of the market.
Yet, if people hadn't written outside the market, we never would have ended up with some truly great works, like Madeline L'Engle's A Wrinkle in Time.
It's a catch-22.
So, how do you decide what to write. Do you go with your gut? Or, do you go with the market?