Here's what we find that helps:
Set your clock to your destination time as soon as you board and abide by that time; if it's bedtime there, sleep, if not stay awake.
When you arrive, stay up as long as you can and get up by 8 am. Try to keep to that time zone as much as you can, and avoid caffeine in the afternoon (but indulge when you hit the 10am slump).
Try to be in the sunshine as much as possible the first few days.
Don't take a zillion things in your carryon, but if you can fit a pillow/neck pillow in there, do it.
We've had friends who start moving bedtime back/wake up time up in small increments the week before they leave, to help them adjust to the new time zone.
Where are you going?