Tips on being confident when getting on a bratty horse?

Lunge him first and just remember to relax and stay confident. Even if you don't think so, act like you know you're in control and YOU ARE THE BOSS. If he seems like he's going to spook then circle or get his feet moving, its a lot harder for them to get silly when they're trying to figure out what you want from them. Be firm with the reins and just keep in control as best as you can and if he does spook and buck and you stay on, kick him and discipline him, make him know that's not okay. If he gets you off, go back to lunging him for a bit, then get your nerves back together and start over. You really have to be consistent and make him respect you and know that nothing he does is going to get him out of work... good luck!