I won't give you any specifics like "see this" or "do this" because it's Europe, as such it is all essentially the same. I will offer some important tips to help you get along in their culture. Above all, remember you are representing America, so act like it!
1. Don't attempt to speak their language. You won't get it right anyway and may just insult them. Insist they speak English or walk away.
2. Speak up! Most Europeans will have poor hearing from bad nutrition and/or the constant bombs/gun shots going off due to their constant wars. You will need to practically yell to get your point across to them. If they are not seeming to understand you, speak up and repeat. You can usually get something across with the proper volume.
3. Flaunt your wealth, BIGTIME. This is kind of a fun suggestion. All other countries all assume Americans are big time millionaires so play along and show off! Don't be afraid to flash a lot of dollars around and assume everything is for sale.
4. Look at european women all you want. This is not America, feel free to visually undress any woman who is pleasing to the eye. It is part of their generally perverted culture. Whether they are with a guy, in church or 13 years old, let your American eyes take a nice long stroll around. Many women will be offended if you don't look down their shirts or up their skirts, and sometimes comment that you are appreciative.
5. Do not try new foods. Feel free to comment on foods that look/sound weird. They eat some whacked out stuff over there and the sooner they realize the Americans think that is gross, the sooner they are apt to change.
6. Get physical. Europeans LOVE Americans. They simply love us and you will generally be greated like a conquering hero wherever you decide to go. On the off chance you are not, feel free to kick somebody's ass. Physicality is often all that Europeans understand and, because you will be bigger and stronger than most of those runts, you really can't lose.
7. Comment on odd smells. Lots of folks over there do not use deodorant but what a lot of Americans don't realize is because they don't know much about deodorant. If someone smells offensive, quickly ask if they have heard of deodorant and tell them all about it. If they do not seem to understand make sure and mime the application of a roll on deoborant to your underarms or, better yet, insist they take one of your airplane size sticks. They will truly appreciate your gracious American assistance.
8. Get drunk. Tons and whenever you want. Make sure to remember 1-7 above though when you are drunk.
I am sure there are a few missing but the above have always worked great for me.
Happy travels.