I find it helps me to find sort of a center of gravity or center of symmetry. It's harder on some than on others, but it makes them roll straight. Like for instance with Tentaclear you use the two thinner, rectangular panels as a guide. Point that where you want it to go and it will roll fairly straight, even if it doesn't keep a steady speed. I roll my Storm Skyress so that the panel may pop open but the ball rolls that direction and shuts in momentarily.