Originally Posted by WMR
Don't advertise the fact that you're American.
I think this is a fair statement, but not in the way you might think. Of course you will likely stick out as an American even if you try to look "Euro." It took me a good year in Austria before strangers didn't automatically think I was American. However, I think it is important for Americans traveling to Europe (or any foreign destination) to be somewhat self-aware of how you might be perceived in a foreign context. Most Europeans will be very friendly with Americans they perceive as nice, but no so much with people they deem obnoxious. Here are some tips based on my experience:
1) Always remember that you are a guest in their country. If you wouldn't do something when invited over to someone's house, don't do it in someone else's country. However, don't feel like you need to hide being an American. I've met some of the most interesting people who wanted to talk to me simply because I was an American. You'll meet jerks as well, but that can't be helped. Every place has its jerks.
1a) This is not Disney. Just because someone is wearing traditional dress does not mean that person is there to entertain you. For example, if visiting Salzburg, Austria, don't comment on how the locals are dressed up just like the "Sound of Music Kids" or ask them to sing "Edelweiss."
2) Don't talk so loud. Nothing says "Here come obnoxious Americans" more than a group of tourists speaking English so loud you can hear them 1/4 a mile away on a crowded street.
3) Learning "please" and "Thank you" in each language goes a long way.
4) As has been said earlier, it's best to save the shorts for the beach. The reason being that if you are checking out museums or churches, shorts are considered inappropriate.
5) Leave the sneakers in your bag unless you're taking a morning run. Instead, wear comfortable shoes with sturdy soles. You will be doing a lot of walking and cobblestone streets can be murder on your feet if you don't have the right footwear.
6) Keep your head on a swivel, especially in Train Stations, Metro/Subway stations, and large public squares. While you probably won't run into terrorists looking to take you down, you will probably run into pickpockets and thieves. Gypsies are real and you will run into those who fit the stereotype, especially in Southern and Eastern Europe. Rome was the worst in my experience. Avoid groups of children hanging outside the train station, aggressive female beggars in pairs or more, and don't let crazy people on the metro distract you. Don't be afraid, just be aware.