As a German person I can confidently say Schatzi and Liebling are reserved for your girlfriend/boyfriend. Special cases exist, for example a very close friend you want to tease with those words. NEVER to a stranger!

In general I have disappoint you: Germans simply don't flirt as much as you guys. We are also not very comfortable with strangers talking to us. I would recommend to simply address people by their name or just say Hi. You will do just fine.

For the simple everyday life, laogui and adrian already said enough. Don't worry!

To understand what's going on around you I can highly recommend you to download the apps Wechat, create a Weibo account and maybe a Meipai account. The conversations you have with Chinese locals are probably going to be light - where you come from, how you like Chinese food, how long you want to stay. Add every one you know on Wechat and Weibo and read what they are writing. This is where the big party is going on that most expats miss out on - political discussions, movies and music.

A world will open up in front of you. Don't be afraid to enter. 

Great article!