Real tips and near-misses from people living in China, pinned for the people about to arrive. Read theirs, then pin your own. A name and a real avatar are part of the deal: public words come with a face here. New notes go up after a quick human check, usually within a day.
Set up and do the passport verification for Alipay and WeChat in your home country, before coming to China. I did this with Alipay in the Netherlands and had no problems at all here. I downloaded WeChat after arriving and had a lot of problems with it.
Every time you move to a new address, or even re-enter China, register with the police within 24 hours. Hotels do it for you automatically. A flat does not. The online form takes five minutes and saves you weeks of paperwork later.
One concrete thing you wish someone had told you before you arrived, or right after. The more specific, the more useful.
Your name and a real avatar photo are required. This board is public, and public words come with a face. Notes are read by a human before they go up; anything spammy or unkind simply never appears.