Desensitization to everything you can.
Haltering, leading, tying, grooming manners, farrier manners, trailer loading
Get one of those leadropes that are not too long when he walks but when he bends his neck to eat and steps on the lead rope he will freak out and he will try to take it out... do this in a pasture where no one will get hurt:))
I have a 7 month old and we groom him, pick up all feet, put boots, polos and wraps on him, put a bit in his mouth, longe him, walk and graze him, jog him and walk him over poles. He will probably be a showjumper