So I have taught my seven and a half month old colt to, stand tied, be groomed, pick up his feet, lead, get use to fly spray, clippers, and not to bite or kick (he knows im the boss)!! Is there anything thing else he should know?
Once he is good at being in the trailer, if you have friends at other barns and have the resources to take him to new places, I'd start with that as soon as possible, especially if you plan on showing him. So many horses suffer from such anxiety when they're away from home :(
You should look up in hand trail events. Teach him to trot next to you, go over poles, pivot in a box, back up through an L shape, sidepass over a pole, open a gate with you, square up, go over bridges/tarps, etc. :)
Can you touch him all over, even in his private areas without him freaking out? That is a good one to teach them. If you imprinted him at birth he is probably already ok with it. But ya know when it is sheath cleaning time when he is older, it is nice to have them not panic when you grab their stuff