When flying west and changing 5 or more time zones you want to land in the (early) morning or evening. Avoid landing in the middle of the day.
When flying west and arriving late in the evening, try and arrive deeply tired. Push yourself to not sleep at all on the plane. Then eat & get 8hrs sleep when you get there. Don't nap at all next day.
When flying west and arriving in the morning, try and sleep at least 8hrs prior to landing. Stay awake & DONT nap the next day. Stay up until 11pm or later. Wake up in the morning and stay up all day
When you want to be fully rested before landing & the flight is 8+ hrs consider taking a sleeping pill you've tested in adv. that *knocks* you out. If you wake prematurely take 1/2 pill right away
If you need to sleep on plane in preparation for morning arrival, consider getting a bad sleep the night before.
Drink lots if liquids always.
Melatonin is great to take before trying to get 8hrs of sleep in the new city, but only for when you go to sleep in late evening. Fight all urges to nap during day.
Get neck pillow, eye mask and ear plugs for flight. You don't want to waken prematurely.