Does your horse stand quietly on loose reins when the pressure is off? Or are they more likely to paw at the ground, dance around, and nervously want to keep moving? Learn to recognize the difference between a Type A and Type B horse, and master the paradox of energy vs. relaxation for each type.
With horses, just like with people, let your actions speak for you. For example, you may think you are rewarding your horse when you say "Good boy" or "Good girl"… But if you don't also release the aid, your horse will not really feel
Always sit the trot for a least a few strides before asking for a transition to canter or walk.
It is common for riders to accidentally teach their horses undesirable behavior by releasing the pressure of an aid at the wrong time. Be mindful of only rewarding behavior that you actually want.
"Incorrect training is as if you buttoned a sweater wrong. In order to fix it you must unbutton it and start over again." ~ Reiner Klimke You cannot just add another layer over the top and expect it to be right!