And the the very first "tip" listed underneath the above steps:
1. Relax mentally. You have to relax. If you fear that the pain will be more agonizing than what it actually will be, it'll hurt even worse.
2. Breathe. When someone punches you in the stomach area, breathing out hard and swift will take all air out of your stomach so that they don't knock the wind out of you. Tighten your abdominal muscles; it will help protect vital organs. Try not to double up or bend over. Instead, stretch backward slightly if you can/if the situation allows it.
3. Visualize getting hit hard. If you can visualize it, you can take punches a lot better.
4. Don't panic! If you panic you will have a hard time recovering from a hard blow. You'll be suprised how fast your body will recover after a hard punch.
5. Have a short memory. When you get hit, try not to think about it. Not thinking about it helps the pain go away. Remember that pain is temporary and there are worse situations you could be in. Scientifically, pain is only in your mind. Its your mind telling what just happened, if you think of that, it won't be so bad.
6. The best thing to do is be proactive. Do not look in your opponents eyes, watch the area of his/her collar bone, not only will you be able to tell that they are going to punch you you will be able to tell what hand they are going to do it with.