From a very frequent flyer and former European resident:
- avoid fatty foods two days prior to flight. Eat small light meals
- set your clock to your arrival time as soon as you board the plane
- sleep as much as you can - sleeping pills can help, if you can tolerate them
- as soon as you land, adapt to the new time - if it's breakfast time, that means staying up as late as you can, perhaps with a small afternoon nap. If it's dinner time, go to bed a few hours after you land
Unfortunately, it's usually worse coming from Europe to North America, sorry to say! I rarely have jet lag issues now, and just think - you will be waking up early in the morning to start each day at WDW!!
Hope that helps!