After hearing several good reviews, I’ve been playing with Timeshifter to help with jet lag. From their marketing material:

Generic jet lag advice is, well… generic. It won’t reduce your jet lag and can actually make it worse. Each traveler and trip is different and requires a personalized approach taking your sleep pattern, chronotype, itinerary, and a range of personal preferences into account.

After two trips, the advice the app generates has been working really well. It doesn’t eliminate all the symptoms of jet lag for me, but the fairly mild symptoms I do have on longer trips are compacted nicely into just a few days. The app isn’t cheap to use, but anything that helps beat jet lag is worth a lot.