Exercise. Ideally, you should be in shape before your trip, since your body will be able to face jet lag much better when it is physically conditioned. You also can work out once you arrive.
Don't drink alcohol or ingest anything containing caffeine. Alcohol and caffeine cause dehydration and can mess with your sleep schedule. Alcohol also can cause nausea and caffeine can increase anxiety.
Drink lots of water on the trip. Bring your own water, if it's allowed. Staying hydrated will help reverse the effects of a plane's dry atmosphere.
Follow the schedule of your destination. If you arrive in the morning, even if it feels like midnight to you, eat breakfast. This will help your body recognize and adjust to the pattern.
Get lots of sun. Sunlight makes your hypothalamus reduce melatonin production, which can help you stay alert during the day and reset your internal clock.
