Learn how to bob & weave effectively, learn how to torque your body into punching power (hooks will be much more effective once your on the inside), keep your hands up, learn proper footwork for getting and staying inside an opponents guard (if your familiar with the term "clinch range", that's where your going to be most effective for the type of fighting you are attempting to learn. the closer the range, the tighter the hooks, the stronger the hooks will be). Feint like you are going to try and get in close fast, then actually do it. That'll throw your opponents timing WAY off.

It doesn't hurt that many of the fighters that utilize this style of boxing are built like tanks.

Oh, you are going to take some punishment learning and using in-fighting (the style your are talking about). Tuck that chin into your chest. A glass jaw is pretty weaksauce. If not proficient, i'd work on big right overhands (if orthodox), hooks to the head, and shovel hooks. Oh, and never ever neglect the jab.

Good luck, as a fighter who prefers to abuse the jab and use my gorilla arms to stay on the outside, nothing is more frustrating to me than trying to keep shortys out of my guard. I like firing hard crosses and jab/uppercuts if i see an opponent trying to get close. Watch out for that.
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If you want to play, train your body. If you want to win, train your heart.