When around horses, do not yell or make sudden, animated body movements.  This behavior could startle a horse, or several horses, leading to running, bucking, and chaos.

Never approach a  horse from the rear.  Walk around, so that you are in his field of vision.  It is best not to walk towards him straight on; try to place your body so that it is facing his left shoulder.  Walk at a normal pace, and speak to him in a soothing voice. If the horse does not know you, stop a short distance from him and let him look at you.  Do not look the horse in the eyes.  Keep your body soft.

Once you're near the horse, allow him to smell you for as long as he likes.  Once he has investigated you, you can attempt to stroke him.  Generally, it is best to stroke the side of his neck.   If you attempt to stroke him on his nose, he may startle or pull his head back.  A horse needs to trust you before you can try rubbing his face.

If you need to walk around the back of the horse, keep your hand on him/her, and allow your hand to glide on his back and on his hindquarters as you walk around to the other side.  This allows him to know that you are still there and he is less apt to startle.