Iseul, getting your horse to stand still is fun. No halter. Stand in front of the horse, barely to it's left, hold your hand up like a stop sign and say "stand". Place your left hand on the neck and start walking down it's side with your hand sliding along it's back. If the horse moves, go back up front and start again. When you can make a complete circle repeat only move just out of reach and circle. Before you are done with teaching this, you should be able to ask the horse to stand and walk a huge circle around it. This then advances to leaving, grabbing a carrot and hiding it and if he's still standing he gets the reward. If he moves a step, put him back and again leave and return. When he gets the reward, leave him alone for a few minutes by walking else where and having your back to him. When the horse is solid with this, you can groom, saddle, pick hooves without being tied. The more freedom we give them, the better they stay.