In addition to the information in Travel Tips 1, here are some of the things I've discovered about international travel. Most of my experience is with European travel so keep that in mind. I can't comment on Asia or South America having never had the opportunity to go there, yet. In order as they occur to me:
1)Pack a snack in your carry-on. While airline food has gotten better it still isn't very good, portions are small, and usually there is at least one item in the meal that is totally gross. Plus, if you don't eat the snack on the flight you can have a nosh sometime later during your trip.
2)Research your destination. Inevitably there isn't time to do everything you would like to do on a trip. Researching will enable you to make your top five or top ten list of must dos and sees and by focusing on those you will feel less rushed and also will get more out of the trip. I loathe the types of tours that drive you past everything but don't allow you to explore. Hello? I may never get back here!
3)Photograph the unexpected or unusual. Everyone always wants to photograph the big things, like the Effiel Tower, and by all means snap away. But save time and either film or card space for the small things. You can always buy postcards of the big landmarks (and more often than not the pictures on those are way better than anything the average tourist can achieve-face it the pros have better equipment, better access, and more talent) but they aren't going to have postcards of that funny sign or that cute dog or any of the other myriad other things you will see on your trip. And even more importantly, remember to photograph the people you are traveling with and make sure they take a few of you too.
4)In order to use your cell phone overseas you must have an international plan as well as having it activated before you leave. If you don't have the international plan take your phone with you anyway. The new ones all have alarm clocks on them which can really come in handy, even if you only use it to serve as a reminder to finish up and meet your tour bus. Don't forget your charger!
5) Buy an adaptor. Pack it in your carry-on. A lot of people will tell you that they aren't necessary, but in the age of cell phones, digital cameras and other tech devices you are going to want to plug something in at somepoint. Trust me. I was the only person in my group this past summer to bring an adaptor and I became seriously popular when everyone needed to charge their cameras.
6)Get a travel hair dryer. Virtually every hotel and motel in the US has one of these, but this is not the case around the world. This is especially true if you aren't staying in a big name hotel. If you can do without for whatever reason don't pack one. But don't say I didn't warn you.
7)It's the Americans with Disabilities Act, not the world wide people with disabilities act. Older hotels, B&Bs, and other picturesque lodgings don't always have elevators, ramps, wide stairs, hand rails, or any of the other aids of access that we have here in the states. They also may not have A/C either, but that's neither here nor there. Keep that in mind when you are packing your bag and picking your lodging. Make sure you can lift your bags or that someone in your party is willing to help you out. If you know you have trouble with stairs request that your room be on the ground floor. If you are going to go the route of big name hotels and/or resorts you probably don't have to worry. You'll also be missing out on a lot of the fun and charm of traveling though.
8)If you are staying in one hotel for the duration of your stay or at least for a number of days ask if they have a safe and lock up your passport. Make sure you have another form of ID on you when you go out but put that passport away, as well as part of your money. You don't want to be spending your entire trip at the US embassy filling out paperwork because your bag was stolen with everything in it.
9)Find out if you are expected to leave your room key at the desk each day. This was the case with all of the hotels we stayed in in France and after we got over the initial trepidation it gave us quiet a thrill to breeze up to the desk and say "Chambre Vingt et Une s'il vous plait."
10)Learn some basic phrases in the language of the country you are visiting. In this day and age English is incredibly common but everyone seems to appreciate the effort, even if all you can say is "pardon me" "where is?" and "slower please, I don't speak." At the bare minimum you should learn please, thank you, how much, bathroom, and help me.
11)Be a tourist. That sounds silly doesn't it? But a lot of people I know either think it is beneath them to do the "touristy" things or don't want to take pictures because then everyone will know they are a tourist. Big deal! You are a tourist. Enjoy yourself! Take a picture with the red phone box in England. Sit in a cafe and eat a croissant. Go on a gondala ride.
12)At the same time, don't be obnoxious. Make an effort to speak the language. Try the local cuisine, particularily if they are known for a certain dish. Ask at the hotel for recommendations of local restaurants. I'm still getting a lot of mileage out of the story of these two girls from my high school whose first meal in Paris was at a McDonalds. They felt sick the rest of the afternoon. Guess what folks! You aren't in the states and things are different. Instead of whining about it, enjoy it. Look at it as an adventure. If all you are going to do is whine about "it's not like this at home" then you should stay home.