Well one of the most important thing is to learn balance when throwing more than one punch at a time.
Quiet answer summed up the importance of shadow boxing, thats very Very important....it teaches you balance, proper form and helps you develop your own style.
Bag work....alot of people say different things on bag work. Me personally i try to punch all the way through the bag. But my mindset is to punch through the bag before my hands even get let go.(might sound confusing, but i dont know how else to explain it). When my hand lands i dont force it through the bag, i pull it back after full impact. The way i punch is i kind of whip my punches out there instead of trying to muscle em out, this really works for me, so i stick to it. when you whip, whip fast! Well you best advice i can really give you is practice, through practice you experemt and find out what best works for you...good luck!
