There was quite a bit of research that went into my Editing Checklists. In case you want to do your own research, here is the list of books I poured through (intensively). Maybe you'll find other things in there that speak to you. If so, let me know!
1) Self-Editing for Fiction Writers (2nd edition), by Renni Browne & Dave King- by far the most helpful book I went through. Doesn't cover any genre in particular; the book is more about refining your writing style so that it both sounds professional and reflects your distinctive voice. Highly recommend!
2) Writing Romance, by Leigh Michaels- excellent advice on creating realistic settings, and a very helpful "Characters" section, which includes advice on writing secondary characters that come off the page.
3) Writing A Romance Novel for Dummies, by Leslie Wainger- the first romance writing book I ever bought. I still find useful information every time I read it.
4) The Everything Guide to Writing a Romance Novel, by Christie Craig & Faye Hughes- great starter manual for romance writers.
5) The Romance Writer's Handbook, by Rebecca Vinyard- brilliant sections on dialogue and the different speech patterns of men and women. Plenty of other good stuff, too, but those sections alone make the entire book worth it!
I have many other books that I refer to before and during the writing process, but that's another post. Stay tuned! I promise I'll share!