I was going to write about ginger and see that others beat me to it. It is an old Chinese remedy for stomach upset. It worked for me when I was pregnant to eat ginger snaps. But the best ginger ale you can get rather than a cheap brand. Verners is a good one. It comes in cans and I get it at Safeway. There may be some good bottle brands as well.
The looking out the front window is good to. The person has to watch the road and act as though they are the one driving the car, so they are turning the car mentally as the driver is turning. Just looking aimlessly out the window will make you motion sick. I found that on the flying chairs at the amusement park. It started to make me sick watching the world whirl past me so I focused on my daughter one seat ahead of me, she was moving the same speed as me, so I lost the ill feeling.