Use this tool to get an approximate measurement of the Axis Tilt & Rotation of your ball. To do this you will need to place an easy to see marker, like a piece of bowler's tape, on the PAP (Positive Axis Point) of the ball. Your pro-shop operator can help you with this if you don't know where it is.
Take a photo or video that shows the ball after it leaves the hand. Get as low as possible and position the camera so that the ball is travelling in a straight line away from it at the point of release. The sharper the image the better. If your camera has a slow motion or high frame-rate option this can often help considerably.
Open your photo or video. If it's a video pause it at a point where you can clearly see your marker. Pinch to zoom in and drag to position the ball exactly in the circle.
Tutorial Video: Bowling Ball Axis Tilt and Axis Rotation