Another lesson to work on would probably be transitions, transitions, transitions, Collection, collection, collection. From a forward, lengthening trot to a normal trot, to a collected, slower trot. From a slow, collected canter to a normal canter to an extended canter. From a canter to trot transition, canter to walk or halt or walk to trot or canter and mix it all up so its not boring for the horse and captures his attention. Make sure to use leg when transitioning downward to maintain the frame. Don’t drill. If the horse is listening and does well than stop. This teaches him that when he listens to you, that he gets to be done. The quicker he listens than the less work he has to do. Don’t forget to praise when he does well too. I find that the horses like to know when they are doing a good job! The transitions will gain you more control with your commands and develop a communication together. This way when he wants to race, hopefully when you ask him to slow down, he will reciprocate.