No PDA
If you're into PDA, maybe try to reel it in when you're visiting China with your boo. Public displays of affection tend to make people uncomfortable, so keep the lovey-dovey stuff to yourself or behind closed doors.
Keep It Cool
If Chinese authorities stop you for any reason, make sure you keep a level head. It's uncomfortable and can be aggravating especially if you're not doing anything wrong, but reacting negatively could lead to bad consequences. Just relax!