For those about to Tweet: twittercheatsheet
It’s all here: 21 tips to consider when you’re working with a freelance copy editor or proofreader. The tips outline what freelancers need most to work to the best of their ability AND keep your budget on track.
If you ever need your editor to work on paper, here’s how to decipher their input. Courtesy Chicago Manual of Style, 17th edition: http://www.eliteediting.com/resources/proof-reader-marks.aspx
Ten Writing Mistakes to Avoid The Ten Mistakes (and Easy Fixes) by Pat Holt