Another good thing to do is stripping the balls with tape to confirm the grip and the ball rotation being thrown. Originally did it for pitching and now use it more for throwing the ball, players hate it when I pull them out.
Here is one I just ran across. Not sure this guy is the best demo artist or that I love this routine but maybe someone else would, or would like to comment.
OK. He is annoying. He doesn't cover grip, at all. And he is one of those guys that stands and pops the ball into the glove, while he is talking. And boy, does he talk. He acted like he was paying for 6 minutes of filming and had 7 minutes of information.