SecondAttempt
Thinks s/he gets paid by the post
It is very simple. You can not magically over come jet lag. It takes time.
Therefore the sensible answer is to already be on local time before you arrive.
I find it much better to adjust at home first instead of wasting the precious time on a trip feeling bad.
Everyone I talk to about this thinks it is a strange thing to do.
They are wrong
This is my strategy. I try to start living on destination time a few days before departure. Living means not just sleeping but also eating on destination time. Honestly, it never really works completely though so my backup plan is to tough it out. Flying to Sweden from Hawaii recently, a 12 hour difference, we checked into the hotel about 2 AM after flight delays and were up at 5 AM, because it was dinner time for us.
We got up, had breakfast, and did our stuff...which was mostly shopping because our luggage was lost. We had a dinner date with a friend so we took a nap in the afternoon. I was seriously crashing around 4 PM. But we were up until late evening, almost midnight.
But each day I had little trouble getting up early but it took several days before the 4 PM crash withered but it did eventually.
My advice is to recognize when you will be most awake in destination time and plan activities for then. Most of us are used to REM sleep around 3-5 AM in our home time so that is likely to be when you are crashing. Just try to plan breaks around that time.
I traveled a lot for business in my career where I did not have the luxury of planning and adjusting. It can be done. Maybe not ideal for a vacation though I admit.
And honestly, melatonin and alcohol both help adjust sleep patterns.