4. Never make someone lose face
The worst thing you can possibly do to Chinese acquaintances is publicly humiliate or otherwise embarrass them. Doing so makes them lose face. Don't point out a mistake in front of others or yell at someone.
The good news is that you can actually help someone gain face by complimenting them and giving credit where credit is due. Do this whenever the opportunity arises. Your graciousness is much appreciated. For example, "Give a round of applause for Laoshi , for giving us a wonderful lesson today" THEY LOVE THAT.