Heck, I've been shooting recurves and longbows more'n 50 years and I'm STILL learning!
Got in front of a full length mirror yesterday, drew an arrow and aimed at my reflection. Found out why I've been having such a problem with 'leftitis' the past few months. My head doesn't turn as far as it used to and my old anchor wasn't under my eye any more. Moved my anchor up from over my second bicuspid tooth to right behind my canine tooth and modified my stance by moving my back foot a little more forward. Now I should be shooting down the middle again.