isolation: Whenever you go to attack an opponents arm or leg, the vast majority of his immediate defense will always come from the OTHER arm or leg. Therefore you must become adept at isolating your opponents hand from his other hand, or his foot from his other foot so that they cannot support each other. Learning to interfere with the other arm or leg so that it can't be used for defensive purposes is a big part of effective arm locking and leg locking. Don't get tunnel vision on the arm you're attacking – pay attention to the other arm or leg as well and you will be much more successful with your arm and leg locks
