Instructions
Practice playing "Wii Bowling." The goal is to get your game scores as high as possible. Bowl games as close to 300 as you can by bowling strikes and spares as often as possible. The higher scores that you accomplish on a regular basis, the faster your points move up.
Rank up your levels and points. The higher you get your points, the more your levels you will move up. Don't let your points fall.
Reach pro level. If you keep your points up long enough, eventually you will hit pro level, 1,000 points, and unlock the diamond bowling ball. Don't let your score drop back down or the ball will be lost to you, and you'll have to earn it back.