Once on board, drink 8 to 12 ounces every hour. Bring your own water supply and avoid alcohol, caffeine, and other dehydrating beverages. The minute you get on the plane, set your watch to the local time of your destination . If it's bedtime there, sleep. If it's mealtime there, eat.
Airlines have a pretty set way of doing things, and mealtime is on their terms.
Our advice is to take your own food. When it comes to in-flight entertainment, try to find an airline that has personal video systems so that you can watch a movie when you want to. Or resolve beforehand that you absolutely won't watch the movie no matter what it is.