What Chinese call each other informally

"Wang Laoban" or "Lao Wang", the restaurant
proprietor at Fanjingshan, Guizhou, where I was
last week.

This is interesting and fun!  What the Chinese call each other informally.  I know, having been in China since 1976, and now married to a Chinese, that it can be a bit of a fraught affair.... With my age now, I can pretty well get away with calling people of a certain age, like Mr Wang above, "Lao Wang" or "Old Wang", and sometimes, again because of my own advanced age, they say to me, "oh call me xiao", as in "small" or "junior", as did the car driver when I was in Guizhou last week.