How do I do it? I do Parelli.

But lets not get off track here...
Some simple things someone can do is like back their horse up WITHOUT MOVING THEIR FEET. In the horse world whoever moves first loses. Sometimes people move way too much. How much can the horse do while we do less? That's the question. And simply asking the horse to respond to steady pressure in different areas of his body is a good way to let the horse know who's who. If you can move your horse's front end around 360 degrees you will prove to him you are alpha. Little things like that. And also not letting a horse come to me with a sour look on his face. His expression must be positive before I give him permission to approach me.