As you cross miles and oceans on a long haul journey, forget time
difference from where you are and where you have just been. Instead concentrate only on what time it is where you land. If you feel tired, say to yourself, “Hum, I am unusually sleepy for only 6:00PM, I hope I make it till 9:00PM tonight when I will sleep really well.”
Works for me -and I change time zones weekly.