The first time I done it I dropped the mouth guard... My tip is don't do that haha! Also just stay calm and don't rush!
1. Stay calm. 2. Don't tell them too much. Only give 1 or 2 instructions and make them repeat it back to you before they go back out. 3. Give them a critique to fix. ie: You're dropping your left when you throw your right and getting tagged. 4. Tell them something that is working against their opponent. ie: When you throw a right to the body, it's landing every time, keep doing that. 5. Don't tell them if they are winning or losing, just stay positive and tell them what needs to be done in the coming round. Even if they ask, just say, don't worry about, worry about what I'm telling you to go out there and do. 6. Be done by the time they call seconds out and have your guy standing (mouthpiece in) a few seconds before the bell rings. Give him a boost at the last second. "Go get 'em!" something like that, just to pump him up. Good luck.
Amy pretty much hit the nail on the head and gave you very good advice. But I would just the same like to stress how important it is for you to be relaxed and calm for the bout. As you probably know, every fighter is nervous before they fight. They need their trainer keep them calm and relaxed, and to be able to trust in them to help them through the fight, whether it be with tactical advice or positive motivation.Do not show frustration or negativity. If you aren't in control or you give off that impression, your fighters will pick up on that, and since boxing is 80% mental, it won't lead to good results. I am sure you will do ok though. You seem like you are concerned enough, you wouldn't have posted this thread if you weren't. Working corners is like everything else, the more you do it, the better you get at it.:tired
Don't tell them "Don't worry, I wont hate you if you lose this. Just dont get knocked out." before the bout.