Eat lightly before embarking on your trip. Try snacking on crackers to absorb excess saliva or sucking on a lemon or an olive.
Take a position near the front of the vehicle, whether it's a car, train or boat.
Face the direction you're headed to keep eye and body sensations in sync with each other.
Keep your eye trained on the horizon or on a fixed spot ahead of you.
Chew intermittently on a piece of fresh ginger or sip a carbonated soda such as ginger ale.
Consider taking powdered ginger, which is available in capsule form. Take two 500mg capsules 30 minutes before traveling, and one or two more after 4 hours if you start feeling nauseated.
Keep the window open and fresh air accessible at all times.