Know how to say words like “hospital,” “diabetic,” “insulin,” etc. in Finnish.
The last time I traveled, while I could navigate the trains and find the bathrooms with no problem, I ended up spending 15 minutes trying to get a band-aid, and that was an inconvenience, not an emergency.
This is usually the most expensive possible way to get Euros or any other foreign currency and in the time of ATMs makes almost no sense. I cannot recall a foreign airport that I’ve arrived in that did not have an ATM machine or multiples of them as soon as I arrived. Most will also have multiple Exchange kiosks, but ATM is normally the way to go. In a place like Finland I can’t see any reason why you would get Euros in advance at the normally gawd-awful US exchange rates.
This statement is not always true. I have had very good experiences using Capital One overseas. It is a good idea to check with your own bank and credit card companies about any surcharges (which I’ve been told are not allowed, but that’s second hand) and what exchange rate they use - how does your CC calculate it?
Finnish is quite an alien language, too. It’s not Indo-European, so even everyday words can be totally unfamiliar. For example, take the word for “telephone” - in almost all European languages it is recognisable, even in Cyrillic languages once you convert the alphabet. But in Finnish, it’s “puhelin”.
If you have a good bookstore where you live you should be able to pick up a pocket-sized travel dictionary that will include every single phrase you might possibly need to use. I wouldn’t waste time trying to memorise too many of them for a short trip. But it’s always a good idea to learn how to say “thank you”, “excuse me”, “I don’t understand” and to know a few basic numbers. People won’t really expect it, especially since so many of them will speak English, but it’ll add a little bit to the quality of your visit.
The last time I was in Europe, also in Japan, there were special local phone numbers you could call that would give you access to very cheap phone services through US operators. When I was in Japan, they charged something like $18 (1800 Yen) for a 3 minute call to the US, while this service charged about $1 IIRC.
But probably a skype account is even better.
I just remembered that service is called USA direct. Here is a link to one such service: http://www.usa.att.com/traveler/index.jsp
I am working on learning some Finnish and it is really not that bad. I’m focusing on the most important words (hotel, train station, hospital, etc.) but I do also have a pocket dictionary so we should be okay. My husband doesn’t really want to learn any Finnish but I am insisting that he be able to say hospital, diabetic, insulin, and taxi.
It’s good to know about USA direct! I will be sure to remember that!
The Helsinki metro has but one line. Nevertheless, I got lost on it because I couldn’t read which direction the trains were going in. (Hint: the train is labeled with the end station of the line towards which it is heading. Which means you have to look at the map. (And I was only going one stop too!))
Lesson: learn words like ‘exit’ and ‘entrance’ and ‘men’ and ‘woman’ and ‘washroom’… I didn’t do this when I went to Finland, not in Finnish anyways. BTW, kiitos is ‘thank you’ in Finnish. It’s on the waste receptacles at McDonalds. 
Donj’t have too high expectations about the aurea borealis. I read the other day that it has somehow disappeared the last years. What you should expect, though, is tango at the karaoke. Or disco dancing.
Most Finns with any kind of education should speak English, so I don’t think that would be a problem.
I enjoyed visiting Kajaani, although it was a few years ago and it was during summer…