Dressage rider and trainer Michael Eilberg, explains three ways to improve your horse's response to your aids
Change his head carriage position
Whilst you’re warming your horse up, think about where he wants to carry his head and how fast he wants to go then do the opposite of what he wants. Working with opposites means if your horse wants to go fast you want him to go slow, if he wants to go slow you want him to go fast. If he wants to carry his head high you want him to carry it low, if he wants to carry his head low you want him to carry it high and so on...this puts you in charge and starts to influence your horse rather than him influencing you.
Ride more transitions
Now that you have your horse listening to you, keep him interested by riding through some transitions. Plan ahead in your head where you are going to ask for an upward or downward transition, so that you can prepare properly and make sure you reward him if he completes the transitions smoothly. Transitions are more than just walk to trot, trot to canter, transitions also mean riding from your normal trot pace into a medium trot or when you’re cantering, pushing them forward for five strides and then bringing them back.
Establish an even rein contact
You’re aiming to be able to have a consistent contact with your horse. Once you have a good even contact, make some changes of rein across the diagonal or in a figure of eight. Be sure to maintain an even contact, which means keeping the same amount of tension on each rein. Make sure you give him a good walk round on a long rein to cool him down