Traveling internationally is such a privilege that we take for granted in this day and age. We have the technology and means to get there quickly and to travel alone with all the apps on our phones. Yes, it's a great opportunity to see and experience all that the world has for us, but it's important to understand that we Americans don't really have the best rep when it comes to respecting other people and their cultures.
Wherever you are, know how to say a couple of lines in their language. The last thing you want to do on your travels is to be lost + piss off the locals because you don't know how to speak their language. Speaking in a broken accent is better than not trying at all. Usually folks will appreciate that you're even trying to communicate in their language.
Read up on their history and culture if you have time. I know this is a lot to ask but it does bridge the gap between cultural barriers and understanding why things are the way they are. What is the cultural etiquette? For example, in Italy, everyone is expected to cover their legs at the churches; in France, people greet one another with kisses on the cheek; in Korea, there is a specific etiquette in drinking settings. Learn some of the more essential cultural differences so you don't look ignorant. ;)
things to consider...
What am I missing? Comment below and let me know!