How do pilots fight jet lag?
Crew members each have their own approach to this but in general on the long haul routes, as a pilot you have at least 24h layover, so you can catchup on some sleep, walk outside for a bit (depending on the local time) and then sleep some more so you're fit for the next flight back home. At home you have a couple of days off to recover from the trip.

On the very long flights 13h+ the pilots are with at least 4 so you can do a quick nap on board as well.

As a passenger I cope with the jetlag by looking at the arrival time, do I arrive in the morning I will try to sleep on the plane, will I arrive in the afternoon the I will try to stay awake and go to bed early. By doing so I wake up easily next morning and do not feel jetlagged.