See the Editors’ Association of Canada http://www.editors.ca/, the NY, NY-based Editorial Freelancers Association http://www.the-efa.org/, and the Society for Editors and Proofreaders in the U.K. http://www.sfep.org.uk/

Sure, writers can use the technique of letting their manuscripts go cold in order to try editing themselves, and this will catch a certain amount of the editing that’s necessary. But it won’t catch it all. And, besides, it takes forever.

I’m an independent editor and published author who learned my craft through all three forms of professional nonfiction listed above, as well as fiction and poetry. I work mainly in fiction now, mentoring aspiring writers through the process of producing professional work. And I love it–not just for the work itself, which I enjoy a lot, but for the constant stream of enthusiasm and gratitude I get from clients who are thrilled to learn the real differences between amateur and professional writing and to see those differences sorted out in their own manuscripts.