When you approach a strange horse, be aware!
You wouldn't run up to a large dog and pat him on the nose,
so why would you do it with a horse? It's best to have the horse's
owner with you. Remember, these are very large, strong animals
who may spook and run off, 'kicking' as they go. They could easily
hurt you without meaning to in the process! Sooooo, walk up to
him naturally, speaking to him so that he can hear where you are,
and rub him on the neck or shoulder. You should come up to
him on the left side (the side most people mount from) and
keep your eye on his ears. Remember, if his ears are laid back,
he's probably upset and doesn't want you patting his nose!
In this case, back quietly away from him and out of his pasture.