So You Want to be an Editor?
http://www.geoff-hart.com/resources/1995-1998/wannabe.htm

Hart, Geoffrey J.S.
Geoff-Hart.com
1998

Abstract:

Most technical communicators are hired primarily as writers and creators of information, but despite this, many of us must learn how to edit at some point. Whether the reasons are good (to prepare better first drafts for review) or bad (your employer won't pay for a full-time editorial position), the reality is inescapable: at some point you're going to have to edit your own writing or that of a colleague. The problem is that editing requires an entirely different mindset than writing, and it's difficult to make the mental shift from creating to revising.