This article by Annelies Judson, children’s book reviewer, is mainly focused on self-published children’s picture books, but much of the advice applies to any self-published work.

“What I don’t think any self-published author wants is to have boxes and boxes of books from the minimum-size print run sitting in their garage, or having to spend months or years selling one copy here and there to eventually break even. So if I have any advice, it’s this: do your research, accept critique, and pay for professionals.”