[Twisted Minis]

Well the balls they keep on the racks at most lanes are just plastic balls, which don't do anything special. The best thing you can do is try to find one that fits your hand comfortably, and you can comfortably hold by your side without discomfort, or trying to bias your weight to the opposite side to hold the ball up. If you buy your own ball, and have it fitted to your hand, you will notice a difference. Realistically just using the same ball every time you go bowling, and a ball that fits your hand properly (and even better, one drilled fingertip), will improve your game.