Hi there! Long flights are always a challenge for me, I tend to get sick very easily and that's why I always want to sleep the whole flight, it's much easier for me to do that. Here is what I do: I try to exercise, I try to do lots of things on the day before so when I get to the plane I am exhausted and it is easier for me to crash as soon as possible. I always tell the person next to me or the flight attendant to wake me up on the meals (I hate when I miss them) If I am not able to sleep right after I step on the plane, I try to watch something on the entertainment center on the small tv they have on the plane and then, after dinner I take a pill and sleep. I always take of those neck pillows and lots of jackets, cause I feel really really cold during the night, the AC is always very strong and I tend to feel cold.Wear comfortable clothes, something warm, cause as I said before, it is always cold inside the aircraft. I never buy stuff in the duty free store, if you are going to the US things are much cheaper there than anywhere else.You can take alcohol and fragrance in your luggage, which usually can have as much as 32kg and you can take two pieces in international flights. Check with the airline company you bought the tickets, but that's how it works in Brazil.It's a great idea to take a set of clothes on your hand luggage, because more than often luggage gets lots on the way and arrives only on the next day. It's happen to me and it was awful to go around NYC to buy clothes during the winter so I wouldn't get frozen.Be sure to know about the weather of where you are going and prepare for it. Have some water and walk around the flight, it is important that you don't stay in the same place the entire 8 hours you spend there.Hope this was useful! Have a nice trip!