The high-rising fastball is believed to be one of the most overpowering pitches in baseball. Many batters and fans once believed that a strong fastball could actually travel upward as it crosses the plate, but this has been disproven, according to "Popular Mechanics" magazine. It is actually an optical illusion. Such a pitch would need to use the Magnus effect to defy gravity, and this is beyond the ability of the human arm. The real secret in a "rising" fastball is to throw it so it doesn't drop as much as the batter expects it to, creating the rising illusion.
Hold the ball with your index and middle fingers placed over one of the arches that the seams form, with the bridge of the arch pointing away from your other two fingers. This is known as the "four-seam" fastball.
Grip the lower end of the ball with the thumb placed on the closest seam, allowing as much space between the ball and the rest of your hand as possible. Grip the ball to provide as little friction as possible when thrown.
Throw the ball with a strong windup that generates as much force as possible from your legs to the arm. The extra speed reduces the force of gravity and tricks the batter, who may think the ball will be coming in slower.
Throw the ball with an over-the-top delivery and snap your wrist as you release the ball. The snap will help generate backspin that also reduces the effect of gravity.