1. Take lots of reading material for any flights/train trips you are going to take!
2. Buy something to keep your passport in (if you don't already have something) since its so necessary to get around!
3. Pay for
everything w/ a credit card! This way you won't lose money trying to exchange currency! Even McDonalds there will take them! (Although I doubt you'll want to eat @ McDonalds

)
4. Attempt to speak the language of whatever country you are in-it makes the locals a lot more willing to talk to you! Even if you only ask if they speak english in their language, they'll appreciate it! Buy a book that has phrases in several different languages in it! Very useful!
5. If you are going to go sight-seeing to any major musuems or gardens, eiffel tower, castles, cathedrals etc. try to buy your tickets ahead of time so that you won't have to wait in long lines when you get there!
6. If you are taking a night train make sure you don't pack a large bag-there isn't always a lot of room to store bags & if there is you'll have to store it up high (a heavy bag could make it harder to lift it up above bunks)!
7. Take a CAMERA!!! Or several-cameras are usually more expensive there! (And keep it in your carry-on!)
8. And oh yeah-have fun!