Roll with the punches!

Keep yourself loose. Don't tighten up. Keeping loose will help your body absorb punches. Stay on the balls of your feet. Never stand on your heels. That's a good way to get knocked down. When being hit in the midsection (ribs) exhale as your being punch. Being hit while inhailing or holding your breath can be very painful and drop most to their knees. Make sure you are greased up with vaseline or some sort of lubricant. This helps your opponents punches deflect off you better. I suggest greasing up your face and shoulders. You can deflect punches towards your face with your shoulders. Never move into a punch. It just adds to the power of the punch. I suggest not moving backwards either but rather to the side away from your opponents power arm (meaning if they are right handed move to their left). If you just move backwards, you still are in your opponents striking range. If you move to the side they have to readjust to be able to throw anything affective.

Covered more in my online boxing courses. Found on homepage.