Know your limitations. Be honest with yourself and how fit you are. Aerobic conditioning is vital. If you are fighting for your breath, it is hard to pay proper attention to what you are doing. Use the proper techniques.
Abdominal strength is important.
We stabilize our entire trunk through the use of our abdominal muscles. Keeping our mid sections strong is key to preventing injury. Stop when you are tired. If you know you are tired, swallow your pride and quit or take a break. Before and after any strenuous exercise, stretch your muscles.