When I revised A Mage's Power I would find errors so obvious I couldn't believe they were there. At first I thought my familiarity with the material caused my blindness and to an extent this was true. However, there was another cause for the errors.
As I said on my "Useful Problems" post, I like to look for ways to improve the story as I revise it. This is author multi-tasking because while looking for errors I can look for plot holes or a better turn of phrase. However, this means introducing brand new content into a sea of nth revision and can create new grammatical errors or itself be improved upon. Thus begins a vicious cycle of 'revise-rewrite-new-errors-revise-hair pull'. During the final revision I found a solution.
If I change any part of a sentence, I immediately reread that sentence. If I change part of a scene, I reread that scene from the top. I likened it to 'covering one's tracks' and sure enough I found the kinds of errors that frustrated me: tenses that didn't agree, missing words, something unnecessary like a hangnail. By repeating what I had just written I could immediately revise it, catch those simple-yet-embarrassing errors and break the cycle.
Warning! This was the ninth or tenth revision. I would recommend AGAINST doing this on a first draft. At that stage all you need to worry about is getting the words down. Indeed, using this method at the embryonic stage is counter-productive at best. I wouldn't use it during the second draft either because my preference is to take in the story as a whole and look for 'big picture' problems. The nuts and bolts of the issue can wait until the third draft.
For more editing tips see "Editing-Professional Help-or-Not", ,"Inspirational Monday: Whedon Editing", and "Revise-Revise-Revise".
On an unrelated note, my New Year's Resolution is to run a tighter social media ship and part of that is regular posting. I plan to post a writing tip or book review every Tuesday and possibly something on the weekend. This week, however, that extra post will be tomorrow because I forgot about Inspirational Monday.