http://www.amazon.com/Survival-Kit-Overseas-Living-4th/dp/185788292X/ (Survival Kit for Overseas Living: For Americans Planning to Live and Work Abroad)
It's a good introduction to being an American and living overseas, dealing with stereotypes and culture shock, and knowing about them ahead of time, so that you are more prepared to understand them and deal with them more positively.
If you are unlikely to read a 200 page book (even though it is a great one), the main point to know is that there are usually a couple low points emotionally for anyone living overseas. The first one, which is relatively minor, comes around the end of the first month, after the newness and excitement has worn off. The second one, comes close to halfway through one's time overseas, which is funny in a way because, if you are going for two years, it tends to hit close to the one year mark, but if you are going for six months, it will hit close to the three month mark. If you know it's coming, and know that most people do get through it, it can be easier to manage. (The few people who don't get through it tend to fly home at that point, even though they would have done better to stick it out a few more weeks till it passed.) Culture shock is to overseas living what Wednesday is to the workweek.
I certainly went through it during my year in Costa Rica. At a certain point I just felt separate, even judged, for being an American everywhere I went. Then, one day, I realized that the only thing that all Americans have in common, the only thing that makes them American, is their citizenship. There is nothing else that all Americans have in common. From then on I no longer felt any of the pressure I used to feel as the representative of all things American, because I wasn't. I was also able, then, to get closer to the Costa Ricans in my life, because I realized they weren't some monolithic foreign other, either.
There are also some quite good books out there on culture and etiquette for each country. Those are enormously helpful to read before going, and while there, too. Different country, different rules, different views of life. It is always helpful to learn about these ahead of time!
I used to work at an exchange program here for students who came from Spain and Latin America, and it drove the Spanish students nuts that the host family would pick them up at school, drive them home, and then stay in all afternoon and evening. They were used to going home, maybe hopping on a scooter, and going into town with friends. Quite a number of them smoked, too, though that has probably changed quite a bit in the past 25 years.