I always used to feel sick after Star Tours, but kept going on it because I'm a huge Star Wars nerd. I didn't like the idea of taking medication for ONE ride, so I did some research and found the anti-nausea pressure point in the wrist, P6. It's just below the point where the bones of your forearm come together. (Check online to see how to find it.)
It works so well! I just apply some pressure there with my thumb while I'm walking through the line and waiting to load. Depending on the version of the ride, I sometimes find I have to apply a little more pressure after the ride, (There's something about Coruscant that my stomach really doesn't like.) but usually it's not neccesary. It's easy, quick, requires no pre-medicating, no special training, and WORKS.