Being consistent and predictable is the number one way to develop trust. Maintain a consistent energy level, emotions, and demeanor around your horse. Keep your communication consistent by sending and receiving messages the same way – a method that both you and your horse understand.  Finally, continually recognizing your horse's efforts is a terrific method to earn their trust. Giving your horse a few treats after a hard workout, cleaning them, and spending time with them while they graze are all ways to thank them. Even if you don't have an intensive training session with them, just being around them will help them begin to trust you more.