This summer, I studied abroad in Germany for about a month and then traveled through a couple other European countries for another month. While I certainly don't know everything, I do know a few things that I wish I knew before I went.
1. STOP OVERPACKING. Yes, you are overpacking.
I brought two small suitcases (both the size of a carry on) and a backpack. I should have packed less and combined the two little suitcases to one medium one. If you're going to study abroad, there's a 90% chance that you are overpacking when you initially pack. Trim it down as much as you can. Don't bring heels. Bring more shorts.
2. Look up the kitchen and laundry words.
Look, I'm not great at German anyways, but I still don't know what the words for the settings on the washer were. I kind of just guessed based on the temperature and runtime and hoped for the best. Seriously, whatever the language of the country you are going to is, look up the kitchen and laundry words.
3. Get a cellular plan for whatever country you're in.
I didn't realize that the equivalent of a TracFone actually wasn't that expensive. I could have avoided going the month without wifi on my phone, but oh well. It didn't bother me too much not to have the internet with me constantly for a couple months, but it was definitely different.
4. Always make sure you have your train ticket.
This applies for local as well as international tickets. Double check, triple check if you need to. Avoid that fine because it fell out of your pocket in the room at your hostel.
5. Consider reviews seriously when booking hostels.
Nobody is writing those reviews to mislead you. If they say you have to pay for wifi in the reviews, that means you have to pay for wifi. If they say there are free tours at a hostel, than they really have free tours. Pay attention to what other travelers have said.
6. Call your mother. Don't worry her.
She doesn't care about the time zones and your grandmother cares even less. When you get to new locations safely, let your family know.
7. Try the different foods while abroad.
Just check about your dietary restrictions first. Bring emergency snacks though, because you never know when a dietary restriction might be difficult to accommodate.
8. Actually be consistent with your blog.
I knew that I should do this ahead of time, but life got ahead of me.
9. Boat tours without food are amazingly boring.
I went on two boat tours: one was great and the other was super boring. The difference was sitting comfortably at a table with a snack versus cramped with no food. Both were mandatory activities anyways, but the difference was astounding.
10. Start biking places seriously before going abroad.
In the US, biking is a hobby, something relegated to a trail. It is not the case elsewhere. Be prepared for aggressive bikers though. It's okay though because in a week or so you'll be nearly as aggressive in the bike lane.
11. Take a ton of pictures.
Okay, so I did this one, but still super important advice.
12. Be ready to be the representative of your country.
I am not some kind of American Lorax, but that did not stop some of the folks in other countries from questioning me on American politics and society like I make the decisions. I don't mind talking politics and culture, but the degree to which some people hold individual Americans responsible for everything is a little startling.
13. Using the money in other currencies is weird.
Okay, so Euros more or less function like dollars (even if the exchange rate hurts a little) but the 1 and 2 euros are coins. The bills are colorful too. Also, lots of places don't take credit cards. I realize that this is all relative, but at first, the differences are weird. Be prepared to think in a different currency or have to translate everything mentally back to dollars to calculate the cost.
Overall, I had an amazing time abroad but that's what I wish I knew ahead of time. If you're reading this and studying abroad, don't make my mistakes: be original and make your own.