How to become a good boxer?

thank RDJ. My other sport is track running. I have noticed that there really is sport specifikk endurance. In the ring "fat" boxers get less tired than me. I am in much much better running shape than they, but when sparring I get so fast tired. Espesially if I get to agressive. Is there anything I can do to avoid getting that fast tired? I have the endurance but I think I thigthen my body or stop breading sometimes or something.

 

Thank RDJ. My other sport is track and field. Running 400m. I have noticed that "fat" boxers that dont have good endurance still get less tired than me when sparring. They are more experienced than me for sure. But seems like they are more energy efficient than me.
It feels like I am too tense in my muscles and also sometimes I forget too breed. This happens especially If I get agressive or my sparring partner is going hard on me. Any tips on how I can be more energy efficient in the ring?

 

best time 400m 51.1. 800m 1.58. Yea I have noticed I doesent help as much as I believed!
Maybe after some time when I learn to relax.

 

more questions:

1. I have bought some dumbells 1,5 kg (3 pounds) and I use them when training strength. The training I do is from a video series called titleboxing. "speed and power". Ok my question is how many times pr week should I do the exercise? The session last for 12 minutes 4 roundsx3 minutes with shourt recovery. The exercises is for upperbody, shoulders, armes. Its very hard because of the burning in the mucles. I know you should rest at least one day between tradiotional strength training, but this I feel is different. Am I right?

2. Is it ok to do shadowboxing without a mirror? can I use my dumbells when shadowboxing? Whats important for a beginner to pay attention to when shadowboxing?