Genre – If you’re a nonfiction author, your best bet is to choose editors who understand the structure of good nonfiction books; they know what works and will keep readers happy. If you’re a fiction author, select a fiction editor who is passionate about those stories and knows what readers of your genre are looking for. Choosing an editor within your genre is especially important for developmental editing.
It’s always sensible to follow due diligence in submitting your first draft of your book to an editor by making as fool-proof a copy as possible for you because first, it is your own creation, and secondly, a horrid draft sent your editor can end up frustrating both you and him or her. Make your own corrections to the extent you can, so that will make the job of your editor that much lighter and the end result would be a lot more effective.