1. Was mach’n?
Nothing prepares you for the German they speak in Austria.  Having spent my year abroad in Tirol, I now joke I speak Tirolean rather than German because they are two entirely different languages.  The first time someone opens their mouth and exclaims “isch mia wurscht” you will wonder where the hell you are and why on earth you chose to come here and you probably won’t figure out the answer to that question until you’re sitting in your first language class back at university and you can understand everything that people say in Hoch Deutsch but they have no understanding of your dialect whatsoever.  Understanding Austrian German is a huge advantage for the future and it’s something you just cannot pick up from a textbook.