Prepare for your trip by taking extra good care of yourself. Get a good night's sleep for several nights before your trip to avoid starting out fatigued. Drink lots of water to hydrate your body, which will help reduce the possibility of headaches and cramping. For several weeks before your trip, try to squeeze in daily exercise to strengthen your body for dealing with the effects of jetlag.
Adjust your daily schedule to suit your destination. For example, if you're flying from New York to Los Angeles, your body will have to cope with a three-hour time change. For a week before your departure, adjust your schedule back approximately one hour. This will allow your body to adjust slightly and will provide a smoother adjustment when you arrive. For bigger time changes, start the adjustment cycle several weeks prior to your departure and increase the adjustment each week. For example, for a trip from Miami to London, start two weeks before you leave and work up to the five-hour time difference.
Move around during your trip. If you're traveling by plane, get up and walk around the cabin several times to get your blood flowing and work out the kinks in your body from sitting. Simply going to the restroom will increase circulation and allow you to stretch a bit. If you're traveling by car, stop every few hours and get out of the car. Take a short walk to get some fresh air or something to drink.
Break up long trips. If you'll pass through numerous time zones, consider breaking up your trip. Although direct flights are more convenient, they don't allow for a break. A connecting flight forces you to get off the plane and walk around, allowing your body to adjust in increments, rather than all at once.
Adjust to the local schedule upon arrival. One of the biggest mistakes that people make after a long trip is to delay adjusting to the new time zone. This prevents your body from getting used to the change and makes the adjustment more difficult. Instead, step into the local schedule as best you can, immediately upon arrival. Eat meals and go to bed on local time, even if it doesn't seem right. This will force your body to adjust and help ward off jetlag.
