Successful breaking requires four things:
- Proper technique
Concentration means you must ignore everything around you, and the board, and then ensure the other three things are used. Instead of tensing your body in preparation for a tremendous output of power and the eventual impact, breathe deep and relax. Speed is relatively easy to fix, just strike faster, not more powerfully. Do not try to hit hard; if the other three things are also present, power will just happen. When you try to strike with more power, your technique usually suffer.
Ensure proper technique is used throughout the motion of the break. Many people will make practice swings using perfect technique, and then when doing the break, they tense and try to hit hard, which slows the speed, and their technique lapses, they let the wrist bend or they change the angle of the strike.