Help with my pony..? Please?

I have a mini pony, and we've had him for awhile. But the people we got him from must of abused him because he bites and kicks and is pretty head shy, he's gotten better.. But I have two other horses in training as well. I'm taking him to a FFA event sometime and there will be a lot of people and kids. I need to find a way to make him listen better, and not be so shy of everything. This is serious so please only answer if you have had experience or are a pro. I reaaaally appreciate it.