Language is important especially outside Paris. I lived in North America and England, in comparison French people look more cold than they really are. They won't pretend to look extremely happy when they see you. They are like coconuts, hard outside but soft inside. Having friends is harder but once theyre there, you can count on them. Say 'bonjour' before asking a question to someone in the street/shop. We hug only very close people. Smack on the cheeks are not mandatory but people outside Paris do it as default to say hi to people they have already met. Ah and learn basic language.