I guess my main problem is my shoulders. They're always hunched or in some weird position. One of my shoulders was badly dislocated when I played soccer, so I think hunching it is like easier on it, but I know I shouldn't. Another bad habit is I always switch the hand I'm holding the reins with. EG, if I'm on a senior horse, I'll warm up with my right hand with the reins, but when I go in the show-ring, my left hand will be holding the reins.
I guess most of my bad habits stem from the fact, I'm always mucking around when I just ride. I guess if I rode a little better, when I'm just practicing, I might do better in the show ring.