Some things:
Always keep the fingers holding both reins loose. Closing the hand means locking the hand and locking the elbow, which makes the horse's mouth harder and makes it so you can't feel when the horse gives at the poll.
All bending is done with the seat, the outside leg originating the bend.
Finish one issue before starting the next. Don't work on canter pirouettes and flying changes at the same time.
