[Avoid jetlag and airsickness] Travel light
Don't pack what you don't need, especially if you're backpacking. There's nothing worse than lugging around a pile of bricks on your back when arriving in a new city and trying to find a place to stay. Just remember, if you need something, you'll be able to buy it on the road. It's easier to travel with a pack than with a suitcase - suitcases don't like crowded streets, rocky roads or stairs (and subways have a lot of them)!