Most people can dramatically increase punching strength with proper form. Make sure you are punching from the ground and are using your hips to follow through your punches. Aside from that explosive power training like thrusters, jumping squats, plyometric push ups and heavy cleans might help too. Hit the heavy bag a bit and try throwing straight punches while holding a band. That can add some snappiness to those jabs and crosses.
Punch the heavy bag
Shadow boxing
Jodging for stamina
Shadow boxing with 3-5 pound weights
Try to create leg muscles at the gym the best exercise is the squats.
Practice the Straight right hitting the bag
Practice is the best way to improve punching strength
By punching harder
Growing up in an all black neighborhood and school as a white kid, I had to learn how to fight, and it comes naturally. I just need a couple workouts or excersices to increase the power of my punches, specifically my right straight.