As a foreigner in another country, you might feel more comfortable if you research the following subjects, keeping in mind the city, region, and country you'll be visiting. One more thing to keep in mind is your gender, as custom and courtesy relate differently between men and women in most foreign countries.
Forms of greeting and gestures
Courtesy, general attitudes
Eating in the home and at restaurants (meal times, table manners, typical diet, etc.)
Population of the city and country
The family structure including views on dating and marriage
Social and economic levels
Work hours and hours of doing business
Art, craft, dance, music, theater, etc.
Local, regional, and religious holidays
Forms of recreation, sports
Land, climate, weather
Past and present relations with the United States
Economy, the value of a U.S. dollar, exchange rates, etc.