I always try to do a combination or everything out of the following: (some has been mentioned)

Flying US - Europe:

Wake up earlier, go to bed earlier for at least 1,5-2 weeks, so you basically end up getting up at 9am (europe team which is usually 3am NYC time)

Have a full meal (preferable lots of meat and carbs that make me tired) at the airport right before the flight, brush my teeth, clean myself for the night at the airport bathroom / lounge right before I board, buy myself some water so I am independent from drink service in the night

have a window seat (left side to lean against which is my usual sleeping position)

while everybody boards, get myself as comfortable as possible, change my clock to destination time, read with just a little bit of light while taxing and take-off (would be too excited to miss take-off) to get tired

try and fall asleep as soon as possible, of course skip dinner on board (terminal or whatever food is better anyway unless in C/F)

Sleep as much on board as possible but take their light breakfast and have a full breakfast at the destination terminal, stay in light places

Find a good shower

don't under any circumstances take a nap or anything on your first day in Europe, stay active

Have a great day and be happy about being in Europe

__________________________________________________ _____________

The other way round I don't do anything special for time difference, it's usually no problem whatsoever to stay up a little longer. If you have a late arrival (in the US day), I'd try and get a nap on the plane but an hour to two is more than enough.