The quote worth remembering (which Buckell gets from a Smashwords guide): “most books, both traditionally published and self-published, don’t sell well." That's not to say you should give up, to the contrary. But in most cases, the advice you get from successful authors does not work to solve this problem, whatever form of publishing you chose. Buckell's piece does a good job explaining why.
The takeaway for me was that there's really no substitute for hard work, though that's no guarantee of success, not by a long shot. Most books just don't sell well. There's too much other stuff around competing for attention.