This is a great thread. I'm thinking of implementing some heavy bag work into my gym sessions after my weight lifting as a form of cardio. Won't start this till June however. Whats the best way to go about it as I don't wana just hit the bag like a plum and injure myself 
First of all mate id learn to wrap your hands properly just to be on the safe side. Handwraps will reduce chances of you hurting yourself, theres many videos on the likes of youtube that can show you how to wrap your hands better than I could describe it! Much easier to see it and copy the steps. Just make sure it isnt too tight, you'll know when it is because it wont feel comfortable and could cut off your circulation. If done rightly though your hands and wrists will feel compact because the bones and tendons are held together tightly. Wear gloves/bag mitts as well when hitting the bag.
As for hitting the bag itself, make sure you know how to throw a punch properly or you may well learn the hard way by hurting yourself. The key to it is to time your punches to hit the bag as it swings towards you to stop the bag dead. Best way to not get hurt id say, boxing is all about timing, see JMM's KO of Pacquiao for the perfect example, he timed Pacquiao's coming towards him with the perfect shot and therefore it was more powerful because you add your opponents mass to the punch. Boom, your out! Its like the speedbag, you have to time it coming towards you and hit it at the right time or its going to move to the side, for it to go straight you have to time it and hit the sweet spot. Very important timing is. Work on the timing. Id also move inbeetween punches, move around so your not standing still in the same spot. Move always, even when your resting. Plant your feet when your going to throw a punch as well, make sure you plant them to get more power, if your finding it hard to plant your feet after moving around take smaller steps as you move around.
Dont throw single punches either, throw beetween 3 to 6 punches is the rule ive always been taught with, ive always had someone shouting at me that fights are fought in combinations, not single shots. Mix them up as well your combos and dont pose after them, a lot of people do this, they throw a combination then admire their work. In a fight they'd get sparked.
Biggest thing I can reccomend to you though is to learn how to breathe because thats where endurance comes from Inhale slowly through the nose, then exhale quickly through the mouth in short bursts (one burst for every fast movement—punch, slip, dash, etc) that'll keep you from being tired out. Endurance comes from good breathing, power comes from good technique.
Sorry dont know how serious your going to take it, but for anyone else wanting to hit the bag, this might be helpful. Bobby can probally put it in a better way than I can as im not too good as explaining things!
