I fly to the US two to three times a year. So that's a 14-15 hr flight to LA and then anything on top of that depending where I'm headed.
My tried and true tips. Always be well rested. The idea that you stay up late the night before to be so tired and sleep on the plane doesn't work. The smaller your sleep deficit is before you travel, the better.
On the plane try to get as much sleep as possible. Less alcohol is better and light food.
Try to arrive in the morning so that you can spend time outside int he sunshine (hopefully) to reset your body clock. Go for a walk and do something physical to keep you going til bedtime. Which can be as early as 7PM. And the next day voila!!
Don't *nap* during the day as it truly messes up your body clock and you can feel nauseous and really unwell. On one trip with the kids we landed at 6AM in LA from Sydney, went to Target, checked into the hotel and were at
Disneyland by 2PM. The adrenalin kept the kids going and we had the best afternoon/evening!! We didn't make it to the fireworks, but we had lots of fun.
Oh and if you're horribly addicted to caffeine like me, it's a good idea to cut right back a couple of weeks before you fly. Nothing worse than waking up in the middle of the night with a horrible headache b/c your body clock thinks it's midday and you haven't had your morning coffee!!!
We do the same stuff coming home and it never seems to work as well, but I think that's just the post holiday blues.