Exercise and sunlight are the keys to resetting your body's clock. It doesn't have to be MUCH exercise, moderate walking will be sufficient. When your body is telling you it wants to sleep, but the sun is shining, THAT'S the time you need to be outdoors going for a walk. That means, after traveling eastward, do your walking in the morning, and after traveling westward, do it in the late afternoon, before sunset. This probably works better in the summer when days are long.

Don't bother trying to sleep if you're not sleepy, but do force yourself to get up when there's daylight.