First of all, it's good for you.
Whether you're off on an adventure for a good time, or a long time, you're going to run into one or two cultural speed-bumps and the worst thing that's going to happen? You'll learn and grow from those encounters.
From etiquette and behavior, to values and appearance; there's an array of differences that are both obvious and subtle when you travel abroad. The best way to handle anything is to be prepared. If you feel uncomfortable in unfamiliar surroundings and situations, do some research beforehand! Frequent some online message boards in the run up to your departure in order to get some tips from fellow travelers. Always remember to pay it forward upon your return.
Broaden Your Horizons
Respect the culture...respect the individuals...respect yourself!
Avoid making comparisons with home. Embrace the new culture as much as you can comfortably and even step outside your comfort zone from time to time.
Make friends with locals. We know how great it is to run into expats abroad that you can chat effortlessly to, but make the effort to meet new people (safely.) One thing we'll say about the like of traditional Irish pubs is that you'll meet some characters!
Challenge yourself to get out and about even if you feel a little lost. Sometimes getting lost is exactly what you need.
Share the experience! Call back home, be active on social media when you can (but don't let it interfere with you having a good time.)
Language and belief barriers may cause headaches at times, but always keep in mind that they're probably having the same difficulties in dealing with you.
As shocked as you may be about some of their quirky customs, keep in mind that you're just as odd to them.
Be mindful mainly of foot placement, hand gestures, and dining etiquette no matter where you travel.
If there's something culturally significant that you don't want to participate in, you don't have to. Communication is important, so don't be afraid to address your concerns with anyone.
Check out this handy guide we came across (we only wish we'd known about bad luck photography before we went to Cambodia...):