As a guest in a foreign country, you need to be aware that it is extremely important that your conduct be appropriate for your new environment. You will need to adjust to different social and cultural norms and behaviors. After all, one of the basic reasons for studying abroad is to develop an appreciation of new cultures.
Each country has its own set of social customs, so you will have to do some research on your own. Also, remember that you do not have to figure this out on your own. Politely inquire about the local customs and be open and flexible when dealing with these differences.
There is a great resource available to students on-line for more information. Culture Crossing - A community built guide to cross-cultural etiquette & understanding, http://www.culturecrossing.net