How do I underhand in handball?

My underhands are not very smooth. Theyre very clumsy and my hand comes up at awkward angles. Is there any way to improve on this?|||First, when hitting the handball, either on a serve or a return, try to remember to take a step into your hit; this will give added power. Second, don't stand with your body facing the wall. Instead, turn your body to the right or left (depending on which hand you're using) 90 degrees with your body facing the side out-of-bounds lines when hitting. Finally, to hit a "kill" shot more effectively, try to keep your hand straight, fingers together, and put power in the shot.|||When the ball is low try to put your arm down in full length and just walk up to the ball and swing your arm your up (not all the way up).