If you're serious about writing, meaning observant of grammar, you probably don't make errors with homophones often. Daily, you choke at the struggles that other people have with you're and your on Facebook, but you know better than to correct these pedestrians. Maybe...just maybe...when texting quickly you'll mix one up from time to time. That's understandable, though, and if you don't, kudos!
However, beware! There are those phones that lurk out in shadows, waiting to sneak into your manuscript and expose you as a fraud. I've seen them in the work of good friends who have English MAs, unfinished pieces that they asked me to eyeball. In a recent manuscript of mine, Janet caught that I wrote chalk full when it's supposed to be chock full. I know the definition of passive voice, appositives, can dazzle you with my text book knowledge, but DOH, I missed these. Thanks for the catch, by the way, Janet.
Here is an awesome list. Go figure, it was on Wikipedia, but I like to run through it and recall if I used any of these that might be iffy in my print.
If you're waiting for something a little more snarky and comical from me, I assure you some postings are on the way. You know the story The Emperor's New Clothes? I'm the kid who squeals that the king is naked. I'll be pointing out the obvious yet hidden with some song and dance in 2015.