To increase your punching power you are going to need a few things in order to have success.
You should purchase a heavy bag that weighs more than 80lbs. I recommend buying one that weighs at least 100lbs if you can afford it. When training you want your workouts to resemble what it would be like to punch a real live opponent. So getting a 65lb heavy bag is a waste of money unless that is all you can afford then anything is better than nothing.
When buying a heavy bag also pick up hand wraps and a pair of bag gloves. Get boxing bag gloves not the ones that have fingers. You want to be able to wrap your hands and then fit them into your bag gloves. Sometimes however to change things up you will want to wear just the wraps and sometimes just the bag gloves.
The next most important thing you can do to increase your punching power is start working out and strengthening your core area 3 times a week. If you have a weak core your punches will not be as powerful as they could be if you had a strong and toned midsection.
When training your core make sure to change your core exercises around every few workouts to keep your body working hard and tones and strengthened from all different angles. You will also notice that with a string core you are stronger in sports like lifting weights and may other sports your strength power and speed will improve.
Another important factor of increasing punching power is consistency. Consistency is important to be able to improve at anything in life. Practice makes perfect and practice definitely makes you better at what you are practising.
When performing your workouts to improve punching power make sure to do them 3 times in a 7 day period week after week. In no time at all you will feel the power behind your punches. You will walk around with confidence and pride in knowing how much you have improved.
For my full article on how to work out and what needs to be done to improve your power and speed in punching to have that punching power you desire you can find it through this link. HOW TO INCREASE PUNCHING POWER.