Avoid Jet Lags
Stay hydrated. Drink more water than usual to counterbalance the dry air in the cabin.
Avoid coffee, tea, and alcohol.
Eat a good meal. Poor nutrition contributes to fatigue.
Take your shoes off to relieve pressure on your feet.
Try to sleep. This will help to reset your internal clock.
Particularly on a longer flight, get some exercise and stretch your limbs by walking up and down the aisles.
When you arrive take a short nap
Have dinner at your new time. Push yourself to stay awake and go to bed at a normal time.