This exercise can help increase your connectedness with your horse and find your center of balance while riding. You'll need your horse saddled up but with the halter left and a lead rope rather than a bridle. Of course always wear your helmet. You'll also need a friend who can lead your horse. Have your friend hold the horse while you get on. Now, close your eyes. No peeking. (Don't use a blindfold. You want to be able to see quickly if you start to lose your balance and slip off, or the horse does something you need to pay attention to.)
Instruct your friend to lead your horse in circles, serpentines, zigzags, over poles and anything else they can think of and do safely do on foot. You can even try trotting with your friend leading your horse. Keep your eyes closed and follow the motion of the horse with your seat. For more challenge try this exercise riding bareback.

