The knuckleball is one of the only pitches that is more effective the slower you throw it. The knuckleball is hard to control. Most pitchers who pitch it, have no idea where the ball is going to go. When you throw the ball, you throw it from your fingers, not your knuckle. Basically you throw the knuckleball like a regular fastball but slower.

When you are throwing the screwball, you must be at the top of your game. The screwball should only be thrown by knowledgable teenagers and adults. It is murder on your arm. It is basically a reverse curveball, but it is held like a four-seamed fastball. Your arm will come over the top as if it were a fastball. Then when you are ready to release the ball, twist your wrist, your forearm, and elbow inward.