Writing a self published book. Thinking about hiring an editor. Any tips?

Hey everyone.. pretty much as the title says.

I'm writing a book as my first product. I tend to blather on a lot when i write, and then go back and delete stuff. I've done well with blogging and marketing copy, however am worried that this book isn't going to be great if I work alone on it with no feedback.

I've presold for about $3k - probably looking to make $30-50k on this book. it'd be nice if it were a GREAT book, bc that would help whatever I do in future.

I'm guessing I can afford an editor, altho idk what the going rate is, idk what the time commitment will be, and idk how to find an editor. Anyone have advice?