Soo I'm 16 and usually do 3x3 minute rounds..

Will lifting 2kg dumbells and shadow boxing for 3x4 minute rounds help?

Does anyone know any other techniques that will help?

As Mark already stated the speed bag is designed for building shoulder and arm endurance thus helping to keep a boxers hands up

Get an object a little less then a foot high, jump back and fourths over it with your hands up in a high guard.

Speed bag, don't drop your hands keep them at guard, it also improves speed a little and hand eye coordination a lot.

Just practice on keeping your hands relaxed while you put it up.

jerking off oh wait that might weaken your legs lol

Soo I'm 16 and usually do 3x3 minute rounds..

Will lifting 2kg dumbells and shadow boxing for 3x4 minute rounds help?

Does anyone know any other techniques that will help?