Editing should be, especially in the case of old writers, a counseling rather than a collaborating task. The tendency of the writer-editor to collaborate is natural, but he should say to himself, ''How can I help this writer to say it better in his own style?'' and avoid ''How can I show him how I would write it, if it were my piece?'—James Thurber
Lately I've been thinking about what it is I do for a living. It's been the topic of relatively heated discussion around the proverbial water cooler, i.e, just how much meddling should we editors do in a paper just because we've got plenty of time to play with? If an author asks for a substantive edit when all that's actually needed is a proofreading, should we take that as license to go mucking about with their prose anyway? I say no, tempting though it sometimes is to turn into a collaborator rather than remaining a counselor.
To me, looking at editing from a writer's perspective, the best editors have always been the ones that after they'd tweaked my prose I couldn't tell it had been touched. I knew it had because the piece seemed a lot better after editing than it had before, but I couldn't quite figure out exactly what it was they had done that smoothed the lumps out. I firmly believe that when an author sees his or her work after it's been edited the reaction should be "Damn, I (the author) am good," and not "I wonder why the editor changed that section?" or "Where did that phrase come from? I'd never say that."
I don't know if I always succeed in being a decent editor, but I'm starting to have repeat business: authors have begun requesting me specifically when they submit requests for editorial services. I must be doing something right.