You don’t basically. And anyone who is trying to tell you otherwise is trying to sell you something. However you can take measures to stop it from being a completely terrible experience – and with all the traveling I do, I have jet-lag control down to a fine art.
My number one tip is to workout. As soon as you get off the plane, get a good solid hour of sweat in. It will tire you out so that you can sleep later, help to shake off the plane trip and get the blood flowing again, and it will give you a few hours of energy before the inevitable crash.
Next I would advise to get outside and allow the sunshine to reset your circadian rhythm. Sunlight on the skin is a signal to your body that it is time to be awake, so help guide your body through when it should be awake with nature. Even better, combine number’s one and two and go for a run outside. You will get to explore a bit too which is always fun.
Drink water. Lots of it.
When it comes to food and jetlag I have found that if I can avoid eating on the plane, the jetlag is much less horrible. Depending on how long the flight is I will either not eat until I land and it is a meal-time (make sure your meals on the other end are at your normal eating hours), or only have protein shakes (no 31 hours of flying meal free thank you!). Obviously check with your doctor and only do this if it is safe for you.
From morning until mid-afternoon I make a point of being outside, wandering around and soaking up sunshine. But after 5pm I make sure that I stop using screens, and begin to wind down. My favorite way of doing this is to use a sauna, or an Epsom salt bath. If you have neither of these available then some stretching or a yoga routine works great – but nothing too physical. Then I usually read in bed until around 7pm, meditate, and then attempt sleep.
The biggest thing with jet lag is NOT TO NAP. I repeat; DO NOT NAP. It will be one of those awful confused naps that leaves you sweaty and disoriented when you awaken, and it will make the whole process harder to adjust. And go easy on yourself. Your body is dealing with a massive change that it hasn’t adapted through evolution to yet; so don’t go picking any stressful situations if you can avoid it.