Here is a compilation of suggestions:

• Get a good night’s sleep before the flight so you are rested.
• No binges on the night before, or specially heavy meals.
• Carry spare underwear and wash kit on plane. Change, wash face and shave and brush teeth shortly before arrival at destination.
• Eat lightly and drink lots of liquids on the flight, but no caffeinated drinks (coke!) until the later part of the flight. Avoid heavy meals – airline dinners are a lot more sensible today than when I started flying. I have a standing order for veggie meals when I fly long distance. No booze unless you can limit it to one or two cans or glasses. Alcohol and caffeine are diuretics which will drain you.
• Sleep or doze as much as you can. It doesn’t seem to matter whether it is real sleep or not. A blindfold often helps. A neck cushion helps.
• On arrival, get a shower ASAP. Have another before supper if you want. Eat lightly during the day, but let yourself go in the evening. Get to bed at a reasonable time, but try not to sleep during daylight hours. The next morning the body clock should be 99% hoodwinked.
• Exercise (a run or whatever) from the second day on also helps things.
• Carbohydrate loading on the day or two before the flight, with extra protein on the day of the flight, may also reduce the effects of jet lag.
• Try to synch you body clock to your destination i.e. when you land don’t go to bed until your normal bed time in the local time zone