The most important words in any language are hello, thank you, and goodbye. Even if you don't speak the language, knowing those three words will get you by, especially if it's obvious you are a tourist/foreigner. Common courtesy goes a long way.

Wander around. (Best if you do it with friends because it's more fun and safer.) You'll find better eateries that way, and at better prices.

Always have loose change/coins (in the correct currency) because you may just have to take a pesky bus ride from the airport to the center of the city/town.