When coaching baseball, one of the most important aspects of the game is throwing. I have found that an introduction and periodic review of how all of the body parts are involved in making your best throw is most important. You will be way ahead if you make the the warm up portion of the practice a disciplined learning time. It is a good place to review checkpoints from  the grip down to the toes. Starting with the grip introduce the progression and then use the warm up time to review 2 or 3 each practice. Emphasize technique and discipline to be accurate. With younger players the grip check should be constantly reviewed. Grip checkpoints are covered here the other drills are in the eBook, Practice Baseball to Win.