The curve ball has been developed over many years. However, one thing stays constant. When throwing a curve ball, pitchers must keep their pointer and middle finger together against the seam on the baseball. Some pitchers will stick a knuckle or spike a knuckle into the ball which will create a tumbling effect. An effective curve ball is a "nose to toes" or 12 to 6 as the hands on a clock. Dwight "Doc" Gooden in the 1980s had a very sharp curve ball.
The curve ball is thrown by keeping your fingers on top of the baseball as you throw the back of your hand towards the catcher and let the ball roll off the fingers. Someone said this is a violent pitch as you must be very fierce and ferocious at snapping the ball toward the catcher as it rolls off your fingers. There is a notion that throwing curve balls can develop elbow problems for pitchers. However, if thrown with correct mechanics, the curve ball is an effective and healthy pitch for pitchers to throw.
These are some tips on how to throw a curve ball.