It’s far more frustrating and difficult for me to edit my own writing than to edit other people’s work.  That’s only natural, since your own work is your own personal creation, and therefore hard to distance yourself from in order to get a clear view of the “big picture” of what works and what doesn’t.

I just finished the final draft of my novel, and feel like I got into a good groove with the process over the last year and a half of editing it.  Here’s some stuff that worked well for me:

• Focus on one type of editing at a time.  It’s a different mindset to look for technical or grammatical mistakes than to look for awkward wording, pacing issues, or tone and character inconsistencies.  Big rearranges, additions, and cuts, too, are something I generally want to do separately from other, easier fixes.
• If I’m doing quick fixes and notice something major that feels like it might be off, I highlight it or insert a comment to make note of it for later.  Then I can look it over in another sitting, reread it and decide if it really is off, or if it’s something I’d like to get feedback on before making any big decisions.
• At times, I’m intimidated about making sweeping changes to the full text of the novel, as if I’ll get lost and never find my way home with the book again.  To trick myself into feeling secure about the process, I’ll cut three or four chapters that need major work, rearranging, cutting, and/or big additions, and copy them to a separate file called “edits”.  I make all the changes there, and when I’m happy with it, I paste it back into the “official” novel file.
• I keep each draft as a separate file – clearly labeled as “[workingtitle]v1” and “[working title]v2” and so on, so that if the big changes go horribly awry or some terrible computer glitch tries to destroy me, I have the older drafts to refer to for reconstruction.  It’s also kind of cool to go back and see how the story flourished and bloomed over the course of the work I’ve done on it.
• Take breaks between drafts!!!  And I mean a month or two, with a couple beta readers giving you feedback before you get started on the next set of rewrites.  This (a) gives you a little distance from the book so you have fresh perspective going back into it, and (b) gets you feedback to work from.  Also, you won’t be so sick of reading the book that you decide you hate the whole thing and never want to lay eyes on it again.
• If you’re feeling stressed out about a big change or aren’t sure what to do with it, step away from it for a while.  An hour, a day, a weekend.  Not more than a couple of days, or you’ll lose your momentum and have trouble settling back in to your work, but a weekend off from editing is necessary if you’re not going to go crazy – or at least become so frustrated that you’ll get overly critical.  Take a walk.  Get some coffee.  Do a puzzle.  Think of it as your lunch break.  Then get back in that chair and do some serious work!