Just try to not do many cube rotations. For solving the cross, rotations are fine, although solving the cross on top can help reduce cube rotations, but during F2L, the very most you should be doing is one rotation every F2L pair. For LL, if you're feeling dedicated enough, try finding some <R,U> algs with the occasional F to make it easier on your hand. If your hand starts hurting after too many solves, that's good. The only way to get your hand stronger is to practice more.
Why would you want to spray paint your cube?...