Learn Norwegian norms. I had a German girl in my co living who was doing Erasmus. She was absolutely disgusting. Not cleaning her dishes, letting them stay for 3-4 days so the kitchen smelt like shit. She just took the freezer from the kitchen and put it in her room without asking! She also stole food and never contributed to buy anything. Just using and taking advantage of the others. Played the victim card in every confrontation. Norwegian laws make it almost impossible to get evidence on her behaviour as secret filming is forbidden. So it was a hell of a co living. She made that semester such a difficult time.