I believe that there is a "heuristic" to become a successful fiction author, but it is not easy at all. Just write books (not just one) and keep marketing them until you find an audience. Notice that this is based on the idea that for every author there is always an audience, the problem is finding it.
Once your audience knows about you, they will buy more and more of your books (that is why you need to have several books in order to make money this way).
The big problem is that most authors will just stop before writing even the first book. Or, after the first or second book, if they don't find success, they will stop altogether -- they never achieve the critical point after which they are successful.
It is not different from writing non-fiction and market to a niche, but it takes much more effort, because readers in fiction are not so easy to reach as in non-fiction.