Keep your chin down and eyes up. This will protect you from getting hit in the soft spot which is the nose, eyes, and mouth. You want your opponent to hit you in the forehead region which is the hardest part of the head. More importantly keeping your chin tucked and hands up will protect you from getting knocked out.
Looking through some old photos a while back, I came across one of Rocky Marciano when he fought Ezzard Charles the second time around, in 1954. In the sixth round, Marciano’s left nostril was cut clean through. He ultimately went on to stop Charles in the eighth round and retained his title, but not without moments of uncertainty when his corner was unable to do much to fix the injury and couldn’t seem to do anything to stop the bleeding. It’s difficult to imagine the pain he endured for those two rounds.
Invest in body punches. They may not seem to have and effect on your opponent early in the fight, but just keep delivering body shots and watch your opponents punches lose power, movements slow down and fatigue set in. They will fall apart right before your eyes.
The right hand lead, left hook is a great weapon against and unconventional fighter (south paw) Position your front foot to the left and outside of your opponents front foot to avoid their power hand and make it easier to defend against their jab. Once you are at this angle you can deliver a powerful right hand, left hook combo then circle to the left to get out the way.