I have one of the best curveballs in my area. No one can throw one like me. It's all about the grip.
Look at this grip I found the only thing I do different is make a C with my fingers so I chock the ball. I think thats the best way to get movement out of the pitch then I just throw it like a curveball.
Try my grip out you might like it.
Ps. It takes getting use to throwing a curveball that you choke since most pitchers rest there thumb on the ball and I make a C so I don't have any space between the thumb and the ball.