My buff orpington rooster is going to be put in the fair this year, except he is to aggresive. He even attacks me. I'm not sure what to do help me.
I keep lots of roosters, and some are used for show like you plan, and some are used for educational purposes. Judges do not like getting bitten or flogged. Aggressive birds around kids you are trying to teach is a bad situation as well. Several of my free-range roosters are in close proximity to rather small kids so aggression not good there either. So lets get past my motivation for not wanting aggression.
My philosophy is that aggression of the sort you are seeing is now a way rooster is challenging you or trying to keep you out of his space. He does it because he either gets what he wants from you by a change in your behavior (you retreat) or he gets some sort of release by attacking you. Either way, there is an aggression component. The approach I use is to make every effort prevent him from thinking I am part of the pecking order or something he can repel by attacking. First, no fighting with him which means no punishment or doing something he might perceive as an attack on him. Secondly, no retreating from his attacks.
Since he already is up to fighting with you, we need to get him to realize you are not a threat and not something he can whip. Each day, go out and pick him up by the body in a smooth direct manner. If he attacks, pick him up anyway. Hold him cradled in your arm and carry him about for about 15 minutes. Wear a heavy shirt if he is a biter during the carrying about. I do not as skin thick. Then sit with him still in your arms to let him calm down and a bit give him of grain or a tasty bug. Then release him in a pen not unlike you use for holding at a show and stay near him but otherwise ignore him. After a bit, in a smooth motion again, pull him out and take him for a short walk cradled in arms. Take him back to where keep him and release him gently into pen and slowly move away closing door.
At no point do you recoil if he attacks. Experience with this helps a lot.
I strongly suggest you talk to parties well versed in showing chickens. Mindset required for that differs markedly from that associated with simply keeping a rooster with a flock of hens.