Hehe, I'll try and uh, 'pitch in'.
When I used to play, they'd always stick me on the mound or in left field 'cause I was 'teh arm', hehe. Fun stuff, both of those positions.
There's actually a lot involved in proper throwing mechanics. It might help to think of your shoulders as a sling. The 'loaded' position would be where you are about to throw. A line drawn through both of your shoulders should point from behind you, straight through the shoulders and through your target.
You step toward your target (along that same line), and at that point your weight should start transferring off of your back foot and toward your front foot. Then it's time for the 'sling' to unload. You tuck your lead arm in and the shoulders swing around, taking your throwing arm with 'em. At the time of the actual throw, your shoulders should be perpenicular to your target. Follow through naturally to help prevent injury.
If you have access to a good coach, they can definitely help you with this. When you know what to do, going through the motions in a mirror can help too.
Along with mechanics, common sense can tell you that stronger muscles will help with a good strong throw as well. You can do basic upper body/abdominal exercise to get a little more out of yer arm. Have fun!