PITCHING:
Here's the best pitching tutorials on Youtube. But beware, pitching isn't that simple it takes practice. Take this knowledge and work on the mechanics of your style. Find what works for you. If you would like to start scuffing the ball but don't know any techniques then the second video is good. Weather or not scuffing is ethical is entirely up to you.
EQUIPMENT:
If you're going to run a league you need a way to call balls and strikes, right? Why argue about it with your friends when you can build a simple device that settles it for you: a tangible strike zone. Measurements can vary so choose what works best for your league.