Flying long haul I used to change my watch to the destination time when I got on the plane, which does help with jet lag.
These days I take a different approach.
Use the World Clock Function

At least a day before I travel I make sure that the time for my destination is in on my world clock page.
I can then start planning my sleep patterns based on the destination time.
If the best fit is to sleep on the early part of the journey I will aim to be as tired as possible when I get on the plane.
If its best to sleep until just before I arrive I will aim to be wide awake when I start the journey.
This doesn’t get rid of jetlag . . . . but does help.
Transit Airport Time Are Important
An additional ‘Travel Hack’ is to include any transit airport time zones on your world clock page.
After travelling for 12 or more hours its easy to get confused about the time at your transit airport.
You don’t want to miss your connecting flight by making a mistake about the time!