This is always my number one travel rule: be as polite as you can, all the time. I'm always shocked when I see Americans in other countries acting rude, obnoxious, or totally put out that the people around them aren't fluent in English. Just be polite! It helps to do a little bit of culture research before you travel to avoid any major faux pas. If you can't do research, watch the natives around you and behave similarly. If someone doesn't speak English, just be as polite as possible as you point to things and try to understand their language. Being polite to those around you will get you much further than acting like a super-obvious tourist.
