When fighting in Kumite, you must have confidence at all times. Confidence develops from constant practice. Overcome your flaws, sharpening your techniques in which after years of practice you will achieve a state where you can perform your best at all times. Your confidence will also come from having self-control and most important, a strong desire to win. Prepare yourself for the rules, a large audience, and for the referees so you can relax and face your opponent. This requires a strong mind which does not necessarily come with experience. It requires an ability to judge your opponent without mistake and by having faith in yourself. Practicing like the others will not accomplish anything. You have to develop your own technique which fits you, eventually to create your own style of Kumite.
When your opponent is attacking
It is unavoidable not to have your protection weaken when attacking. Therefore, take advantage of that and counter at the moment. always stay one step ahead of your opponent. Know your distance and timing. Never wait for your opponent to attack. You must move forward, forcing your opponent to attack or you'll never have the opportunity to counter. Don't block to retreat and then counter, block to counter immediately or your timing won't be right!
Attack with high speed aggressively and persistently!
Single techniques are easily "read" by your opponent. Therefore, use plenty of fakes and attack without hesitating until the referee stops you. Attacking from the side is effective especially against a larger opponent. It is very important to keep your opponent within your range. Intimidate him with your speed and spirit, using your aggressive attack to weaken his guard so you can always be one step ahead of him.
Use your footwork!
Moving into your technique from a stationary position predicts your movement for your opponent. If you're moving, you can move smoothly into your technique without losing any valuable time. For these reasons, it is very important to develop footwork that's fit for you. Next, know your opponent's best technique so you can prevent his using it. You can do this either by having a strong guard around the region of attack (if his specialty is upper kick, constantly protect your upper body); or lure him into using that technique, and counter when he attacks. By making your opponent's favorite technique useless, you will have destroyed his fighting potential. When you can manipulate your opponent, by moving one step ahead of him, you will always win. Footwork requires strong leg muscles and stability.
Make your body memorize some basic attacking patterns!
Create a basic attacking pattern which is most effective for you. Keep practicing that pattern so it will occur spontaneously. For use during tournaments, you need not know so many patterns. If you can add a few techniques to your pattern as the situation demands, you will have a better chance on scoring and winning.
Never pass up opportunities to take advantage of your opponent's errors!
It is very important to score whenever your opponent makes an error. If your opponent stumbles or loses his/her balance on a kick and you don't make a move, you are only thinking about how to block or retreat. You have to have more confidence and concentration. Even a well-trained opponent makes one or two mistakes in a match so you have to take advantage of that. As a matter of fact, one who can create a situation in which his opponent blunders, will be the champion. It is common to see participants who start aggressively and soon tire during the last half of the match. It is absolutely necessary to have enough stamina to be able to move with full power and speed during your entire match.