Lots of good advice. Big things for me are to try and get some sleep on the plane on the way over, even a short nap is good. Also the short 2-4 hour nap when you get to the hotel. I take a little different approach to the rest of the layover. A lot of the layovers I don’t wait and go to the bar at night. I’ll get up from the nap maybe get a quick workout in and then go out for a walk, maybe a museum, or a bike ride in AMS. If I don’t have big plans I’ll make it back in time to meet the crew for dinner. Sometimes I just go solo for the day.
The big thing for me is to do something on the layover. I find I sleep better if I have been out and busy during the layover day.