If you have trouble with the circle change, try the pitchfork grip. It is easier for many pitchers, especially younger kids and guys with smaller hands. All you do is put three fingers on top of the ball, with the index and ring fingers on either side and the middle riding along top. Thumb is directly underneath, about in line with the middle finger. Throw it just as you would the fastball, and as you get more comfortable, you can start trying some pressure points on either side of the ball.