Having lived abroad myself, I can tell you to not worry about it too much and focus instead on all the great experiences and opportunities you will gain. We all worry about living overseas, but that's completely normal. The most important thing that I discovered was that foreigners are actually not that foreign. There are differences, of course, but as human beings we're much more similar than you might expect. Besides, the differences are the fun part!
In terms of what to do, ask people about their experiences living abroad. Pump them for as much information as possible.
A good way to prepare would include some light travel. Another option is to do a short stay in a country and enroll in a language or culture immersion course. You can also participate in some international volunteer organizations.
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