My wise and wonderful pitching coach---an active major-league pitcher---told me that just about any pitch could be turned into a nice changeup, and he demonstrated several for me and showed me how to throw them. Here are a few ideas, many of which I latched on to and incorporated into my arsenal.
First, the palmball (this is the one often referred to as the "Bugs Bunny" changeup). I acquired this at age twelve, and very effective it was too. This pitch is one of the easiest to work with, because you throw it with exactly the same motion as for the fastball, no ifs, ands, buts or bases on balls! You grip the ball with all four fingers on top and the thumb underneath, sort of cutting the ball in half. You grip it well back in the palm of your hand, hence the name---but don't grip it too tightly, because you don't want to squeeze the juice out of it! You can change speeds on it by holding the ball a little more loosely or relaxing the grip, but remember, you still have to throw it with the same arm motion and the same arm speed!
You might get around your coach's admonition with a knuckle-curve. This is a most devastating pitch which comes in there looking for all the world like a fastball but then suddenly drops, like a glass crashing to the floor and shattering into little bits and slivers. You use any of several knuckleball grips, and throw it like a curve---I threw mine with a sharp karate-chop wrist snap, and you should have heard the batters as they swung and missed by a mile. SUCH language! And if you ask me, I think your coach is all wet.
The splitter is another good one. It's actually a first cousin to the forkball, but it's easier to throw because you only spread your fingers wide enough so that they're off the seams. And you throw that one exactly like the fastball, nothing complicated about that...So there you have it: three possibilities for extra pitches to work up and work with. Let's see---a fastball, a slider and one or more changeups---you're all set! Get in there and get the batters out. :baseballpitcher: