The state of their bathrooms.

Look behind any door that's blocked open...if it's filthy (especially roach/rodent droppings) then you know they don't give a rat's ass about hygiene anywhere else in the place.

I can't think of anything pithy to say here, but I look and see u have 5 posts, or whatever it's called.  That and your question makes me wonder if u have been in chiner or other 'developing' countries b4.  well, anyway, a word of advice...  if u r going to live in places like china and if u r not rich, meaning u might go out and live a bit like a local, u better get that idea of 'hygiene' or whatever out of your head. easiest way I can explain it is,  u don't want to know.

rat ain't bad, dirt is good,  handwashing is for First World.   Enjoy your stay 

I would not worry about the food too much. Dysentry is on everything you touch. Door handles, elevator buttons, the plastic wrapping that your "sterile" chopsticks come in. Its even in the tap water you use to wash your hands with. Sure, buy bottled water... it might be copy anyway, but I would bet my last buck that the guy who put that bottle on the shop shelf did not have clean hands.

You just have to grin and bear it. You will never become immune to it. But after a few bouts of topping and tailing, arse on the squat and head in the wash hand basin, with brown stuff coming from both ends ,it does get better. You get used to not having solid stools. Much in the same way you get used to the red plastic stools collapsing under you as you sit outside a shop

asking other expats where they eat is about the only way to limit your risk, but that's not a guarantee of anything in china, occasionally i have had chinese try to get me to eat at their place and offer to show me the kitchen where the cooking is done and how clean it is, but the quality of the food they buy for cooking could still send you to hershey squirt hell for the rest of the day.

stools are solid, another western propaganda rumor, shameful

Go there around lunch time or dinner time, if the place is not crowded it's no good sign.

If you got sick it was dirty. If you didn't it was probably dirty,.

I just assume everywhere I eat is crawling with germs, I usually still eat there and am usually ok.

I used to know a western chef here who told me that even in most western restaurants you don't want to know what happens in the kitchen.

I know some people think expensive restaurants are clean, but I've seen chefs from upscale restaurants come back from the toilet without washing their hands and go straight back to work.   

You have two choices, a restaurant that looks clean, and one that doesn't. You can merely choose the amount of germs, there is no clean.

Just cook yourself if you worry. All resturants aren't trustful. The main problem is the chefs and the waiters are not highly educated. They are usually have the dirty daily habit. I am probally the few clean chinese.

ive eaten is so many places, in the southern part of china things are dirtier in my opinion.  i look to make sure they have a sink with running water...otherwise, no 'f' way i would eat there.....never got sick yet....... check there oil too and see if they change it frequently or looks clear.

street bbq usually the worst meat, frequently rat! and oil bad, but many other things are good.

Depending on where you live you might be able to seek out Utghhr or Hui restaurants. I think they're generalky cleaner.

I found the lats disgusting even in fairly nice eateries. If you can't squat your dead.