I aim for quantity over quality. I pay to have books ghostwritten for a particular market/niche. I also acquire rights to other self published books and re-release them. Self publishing is all about the marketing.
For ghostwriting I focus on a couple different niches. I work with a company to get the books written. I write for the audience rather than what interests me. If vampires are hot one month I put that out. If it's billionaires the next I do those. I have a couple different "authors" that I write under that stick to each genre (One only writes LGBT Romances for instance). A large part was building up the email lists of readers and managing some social network profiles. Once you build up your following it gets much easier. I know some authors that churn out a book every 2 weeks and people will spend the $2.99 (or read it on kindle unlimited) every time. My release schedule is a lot slower, but I'm trying to find more reliable ghostwriters to speed it up.
Regarding the buying of book rights. I have a publishing company I run that looks for books that are not 'successful' and I make an offer. I'll clean up the book and re-release it under a different author name and do a little marketing. These I aim to cover costs before end of the first year.
