In boxing, there is a clear line between fighting to win and fighting not lose. If you are fighting to win, you have an offensive mindset; whereas if you are fight not to lose, you are the defensive kind who are just trying to survive the round and can't wait to hear the sound of the bell. Fighting to win sounds good but it often ends there, especially if you are up against an opponent who is stronger and more aggressive than you.
It is even tougher to fight if your opponent knocks the wind off you and your instinct tells you to sit down, suffer the mandatory 8 count and hope you can get back up to fight. What if you are in this kind of scenario? What should you do to avoid a 10-8 round or worse, let your opponent score a K.O. at your expense?
First thing you should remember is to train hard. Manny Pacquiao, considered to be one of the best boxers in the world and the best in Asia, said "If you train hard, the fight will be easy." (From the documentary made for his fight against Oscar Dela Hoya.) This can be interpreted to many things but the bottom line is: the best way to avoid hitting the canvas and avoid defeat is to train hard.
Build your strength during training. Do not believe those who claim that fighting in the ring makes you stronger. It doesn't! Fighting will make you tired, weak, and even afraid. But if you have prepared for it well, you have a greater chance of making it and scoring a win over your opponent.
Train to last several rounds more than the actual fight schedule. This is where sparring and stamina training are very important. Sparring simulates your actual fight. Stamina training allows you to last during dozens of rounds of sparring sessions.
Increasing the pain tolerance through strength training and other special training is important as well. Accept it, while the main concept of boxing "hit and not get hit", no matter how good you are, how quick you are, and how smart you are, you cannot escape the punches of your opponent. And since it is a given fact, all you have to do is to deal with it.
Pain tolerance may be one of the most difficult aspects in boxing training but it is one of the most useful when you step into the ring. And no matter how hard you curse your trainer while enduring all the pain at the gym, you will have to thank him once you have realized that you have actually survived the punches of your opponent.
Improve your defenses. I am sure you are familiar with the phrase, "the best offense is the best defense." There is no argument against it. In boxing, defense has 2 purposes, to avoid getting hit and to create an opportunity for a counter attack. Defense has to be either of the 2. If it is not, you are not defending at all.
Finally, focus. Mental training is as important as physical training. Focus allows you to concentrate, think and remain calm. There is no window for mistake. If you want to win, you have to work hard for it.
Your opponent will not give it to so fight once you hear the first bell until you hear the last.