Don’t make these mistakes!
Training with a heavy bag can be a very rewarding experience in terms of results and the satisfaction you will get from being able to throw punches and kicks to your heart’s content. However, heavy bag training should not be a hectic routine, from which you will learn nothing. Certain bad habits should be avoided when training in such a manner, so you can indeed, become a better fighter.
Here is one article I really enjoyed: http://www.expertboxing.com/boxing-training/bag-training/10-heavy-bag-training-tips
What I learned from there:
Stop focusing on hitting hard – Too many people make the mistake of thinking that hitting hard is what they should do all the time when in front of a heavy bag. There is hardly a bigger mistake than this. What happens when you are so focused on hitting hard the bag is that your movements become sloppy and uncoordinated. Don’t be surprised to see how poorly you will eventually hit the bag. What’s worse is that you can also injure yourself in such a manner.
Don’t signal your intentions – The purpose of hitting a heavy bag is to train for facing a real opponent, so stop developing habits that may signal the other your intentions. For instance, cocking your arm back preparing for a punch will give any flesh and blood opponent a clear idea of where you are going to hit next.
Stop pushing the bag – When you are practicing your punches, focus on coordinating your limbs and do not involve your entire body. For instance, when you are using your hands, your feet should remain firm on the ground, and your body should maintain its balance without throwing itself at the bag.
Don’t hold your breath – The action of hitting a heavy bag requires plenty of effort and stamina from your part. Do not waste it by holding your breath while you are landing your hits. This will lead to instant exhaustion and you will feel too tired for another round.