My trainer has taught me, just this week, since we are working on changes-that when you are doing your circles, when you go through the middle, keep your outside leg on. Be really consistent in doing that. THen, when you want a change, switch legs in the middle as you tell the horse to take the other circle. Works for me, and I have always had a really hard time with changes. Just makes so much sense. My trainer is NOT a fan of the counter canter. At all. Love him. He explains stuff so simply.