Palm Up Curve Grip: 4 Seam (Option 1)

The thumb opposes the tip of the middle finger. Pull around the outside and across the front of the ball with the middle fingertip. If the hand/wrist isn't cupped enough, you’ll get some crise spin. If you allow your hand to pronate though release, you’ll get spiral spin.
The curve is one of the most difficult pitches to master, which is why I discourage it as a game pitch for most. It takes a lot of work to get decent movement at game speed. It is a great awareness tool for teaching pitchers how to spin a ball and the lessons learned translate well to the riseball.