I wouldn't recommend hitting the heavy bad every day. I do it once every 2 days. On the days I don't train on the heavy bag, I punch in front of a mirror with gloves on for stamina, punch with no gloves on for and flexibility, and take a 5 lbs. dumbell in each hand and punch very slowly for about 2 minutes. This also works speed. I don't know how many rounds you should do the punching with dumbells in your hand; I do 3.