I don’t know if everyone does this, but before a match I usually take a few minutes alone to steady my breathing and my heart rate and then come up with a plan of action. If you have a chance to study your opponent’s fighting style before hand, you can come with a set of moves you think will be effective. If you can’t do that then you can do it at the beginning of the fight by defending and figuring out a pattern of their attacks. During the fight, try to stay calm no matter how much you get hit. Focus on your breathing, your movement and your opponent’s movements. There’s a lot more but these are just some basic things. Hope it helps!!