The foundation of a harmonious relationship with your horse begins with an understanding of the nature of horses. Tendencies, needs, social structure, and reactions to specific types of pressure are all inherent traits of horses that you can effectively utilize to communicate.
"Feel," "Timing," and "Balance" are the three key elements that you will strive to acquire in order to communicate with your horse in such a manner that the horse understands exactly what is being asked of it, and can respond in the proper manner. All this can be accomplished with a lightness that many riders will never understand or be able to conceive.
Before embarking upon this path of a reciprocal relationship with your horse, where each party learns from and teaches the other; above all you should expect to learn from your horse as much as you will be able to teach them.