On the gameboy games I always tend to alternate B and A rapidly and on the DS games I usually quickly tsp the center of the pokeball on the touch screen. I know it does nothing but it's a superstition from when I played the games as a kid.
I press A + B + Down in that order as soon as the pokeball falls on the floor. It works for me most of the time, I don't know if it would work with anyone else.
I use this exact method except I press them right when the Pokeball opens. I am pretty sure that is does nothing, but, it is a long running habit that will not be broken now.