I SECOND: Michael Totten’s recommendation of Self-Editing for Fiction Writers by Renni Brown and Dave King. Also from Dwight Swain (you know I REALLY don’t get kickbacks from the estate!) my husband found Creating Characters: How to Build Story People very useful. I never needed it because characters are the one story element I “got” for free without having to struggle with it.
As a note, everyone knows I’m a big supporter of indie publishing and self-publishing. Everyone knows you can’t tell what will hit in the indie market. But I can tell you a rudimentary knowledge of the craft will help. Trust me. I’m looking over the shoulders of several beginners doing this. There is no shame in learning.