A copyeditor must be mindful of homophones as well. (words that are pronounced identically or quite similarly but that are spelled differently). You’re probably an expert at the basic homophone pairs and triplets, spotting misuses of there and their or to, two, and too. You should also be able to tell the difference between more difficult pairs and triplets:
If you are unclear about any of these terms, consult a dictionary. (My favorite homophonic mix-up: an author who wrote about a doctor cutting the “naval chord.”)