As soon as I reach my destination I have a cup of tea, something to eat and then sleep for about 13 hours. I make that an absolute rule and I always feel fresh afterwards and never have jet lag.
My best advice for jet lag is to sleep as much as you can on a plane, no matter what time it is. Then, when you arrive at your destination, do some sort of physical activity.
Usually I'm traveling for tennis, so the most important thing for me is to not get jet lag.
When I was living in Los Angeles, I always booked a moisturizing milk-and-honey massage the day before flying to Spain. It was heaven - I never got dry plane skin or felt stiff from sitting in one position.
Eating a lot on the plane is not good for jet lag.
Before a long-haul flight, buy yourself a cheap, big, comfortable pillow. It makes a huge difference.
The jet lag really gets to me sometimes and I still haven't found a cure.
If I'm on a flight for more than 14 hours, I will do this Fresh face mask on the plane. I don't care how silly it looks; it saves my skin from drying out.