(Somehow this draft never got posted. Even though the linked article is 2 months old, it is excellent, well worth your time.
Writing to make a profit in 2013 requires either wild blind luck or choosing to write over-the-line sexual encounters. For this brief moment in history, books are a commodity: far more supply than demand.
Stick with it for 5 years, and the opportunists will have faded away or been pruned by market response.
For now, write because you have something to say. Word toward making a profit 5 years from now.
If you understand that self-publishing is a business which is connected to but not the same as the art of writing, you’re light-years ahead of many other authors.