Keep relaxed don't let the nerves burn up your energy. Try throwing combinations as opposed to just one punch. Don't just jab.....jab....jab. at least double jab and try to get your other hand involved. You should throw lots of jabs but what I'm saying is to mix it up a bit or your opponent will work out your game. Listen to all the advice your coach gives you if they shout things to you while your in the ring try and do them I know it's difficult when your tired but just do your best. Apart from that keep your guard up (I know you've been told like a million times) but also good head movement and constant movement around the ring. Try to box on the front foot meaning try to hold the middle of the ring so that your opponent is dancing round using up their energy instead of you.

just relax and nobody wins in sparring its practice just stay on you feet move around keep him off of you with the jab

Relax...................breathe easy and try not to over exert, but rather, work you opponent's style. Of course the regular do's/dont's Keep you left up, chin down. Head movement always. Good luck.

Who has the better left hook and jab wins.

Know yourself as well as your enemy and you will win. What body type are you? What body type is your opponent? What's his strength and weakness, what is yours. Force the fight to your advantage, style and strength where you are stronger then he is, at. Force. Stay stubborn.