Be sure you put the rope around his neck BEFORE you try to put the halter on when you go to catch him.
After he is caught an d in a safe place, use the fly mask like a towel, rubbing up and down his neck, then gradually up to his ears, and when he is still, but not before, stop, and pet. Then do it again, and "accidentally" go over his ears, then back. Make SURE you are standing straight, and tall, and EXPECTING him to stand still. Not going "it's ok, honey, sweety, darling, whoa, easy, whoa, here it comes....easy, whoa..." If you need to, say WHOA. That means "STOP your feet, NOW".
It is the mamby-pamby, sugar-coated weak mumbling that horses do NOT respond to. They ARE NOT human, they are horses, prey animals, and YOU need to be the leader, large and IN charge.