well he doesn't want to be known as the dead man either, and if someone bitches about him hitting someone in the nuts he can say its tactics cuz it is. You can't win all fights fighting honest and not going for vurnable body parts.
It is also important to know what natural wepons you got
and here are some examples.
The knife edge of your hands, fingers folded at the second joint or knuckle, the protruding knuckle of your second finger, the heel of your hand, your boot, elbows, knees and your teeth.
and some vurnable body parts:
Eyes: Use your fingers in a V-shape and attack in gouging motion.
Nose: (Extremely vulnerable) Strike with the knife edge of the hand along the bridge, which will cause breakage, sharp pain, temporary blindness, and if the blow is hard enough, death. Also, deliver a blow with the heel of your hand in an upward motion, this will shove the bone up into the brain causing death.
Adam's Apple: This spot is usually pretty well protected, but if you get the chance, strike hard with the knife edge of your hand. This should sever the wind-pipe, and then it's all over in a matter of minutes.
Temple: There is a large artery up here, and if you hit it hard enough, it will cause death. If you manage to knock your enemy down, kick him in the temple, and he'll never get up again.
Back of the Neck: A rabbit punch, or blow delivered to the base of the neck can easily break it, but to be safe, it is better to use the butt of a gun or some other heavy blunt object.
Upper lip: A large network of nerves are located. These nerves are extremely close to the skin. A sharp upward blow will cause extreme pain, and unconsciousness.
Ears: Coming up from behind an enemy and cupping the hands in a clapping motion over the victims ears can kill him immediately. The vibrations caused from the clapping motion will burst his eardrums, and cause internal bleeding in the brain. (This is what i've heard, haven't actually tried it, it is very easy to block unless they are totally unprepared)
Groin: A VERY vulnerable spot. If left open, get it with knee hard, and he'll buckle over very fast.
Kidneys: A large nerve that branches off to the spinal cord comes very close to the skin at the kidneys. A direct blow with the knife edge of your hand can cause death.
There are many more ways to kill and injure an enemy, but these should work best for the average person. This is meant only as information and I would not recommend that you use this for a simple High School Brawl. Use these methods only, in your opinion, if your life is in danger. Any one of these methods could very easily kill or cause permanent damage to someone. One more word of caution, you should practice these moves before using them on a dummy, or a mock battle with a friend. (You don't have to actually hit him to practice, just work on accuracy.)