The Art of Editing - University of Leicester
This Study Guide addresses the process of editing an extended document such as a dissertation or a thesis. Related Study Guides are: Writing a dissertation; Using paragraphs; and Writing for science.
Editing and Proofreading Strategies for Revision - Purdue Writing Lab
Very detailed and precise suggestions for what to check as you edit. Rather more concerned with the micro level and somewhat prescriptive but still useful.