Recently, someone was asking me for more information about my trip to China.
Photographically speaking, I would suggest that you pack the film you want to shoot to take with you. Unless you are fluent in Mandarin or Cantonese, it is problematical making oneself understood. I wouldn't have any idea how to ask directions to a camera store, or even more specifically, a camera store that sold 120 film! I do recall seeing rolls of 35mm film here and there, usually in hotel or tourist area gift shops, and they looked a bit dusty.
Some of the best photographs I took on this trip were from wandering into some of the side neighborhoods around the hotels where we were staying. I took a few walks through these neighborhoods and found lots of things to photograph. I made sure I kept track of where I was going, so I wouldn't get lost.
On one of our last days in Chongqing, we wanted to give a small present for our guide. We had the present, and only needed to buy some wrapping paper. This turned out not to be as simple as we thought. We turned to the hotel concierge, who didn't quite understand what we wanted. After trying to give us some hotel stationary, another employee jumped in, and while she understood what we needed, had no idea where we might buy it. They ended up trying to direct us to some sort of clothing store, which might have some kind of wrapping paper, but I think more for purchases made there. We ended up in a book store that had reams of printer paper. We bought a packet of colored printer paper and used that for wrapping paper.
Other things that were difficult to purchase were pharmacy items. In this, we were fortunate to have a guide, who could point out what to buy after we told her what we were looking for. On your own, it's difficult to figure out if the box you are holding is cold medicine or maybe hair dye, when you can't read the package! It's also disconcerting to realize that you don't even know which section of the pharmacy you are standing in. Browsing is sometimes difficult, as every aisle had a store employee watching over it.
Water safety. The water in China is not safe for consumption, unless you grew up around there. In many hotels, the food is prepared with filtered water, but to be on the safe side, do not get drinks with ice or lime slice (a common drink garnish). In restaurants, ask for bottled water (Evian is a common brand). One item that was handy was the Katadyn Water Bottle filter. This is a 3 stage water filter that looks like a sport bottle. It works well and requires no standing time that iodine treatments require. The hotels we stayed at only provided a small bottle of free water, so having an extra source of safe water is good. The downside of this filter is that it does require a little muscle, since you must squeeze it to force the water through the filter. There are whole sections on this subject in guide books, so I'll leave it to you to read up on it.
Restaurants: An interesting concept we came across in a few of the restaurants, was that napkins were not supplied, and when we requested them, we were given a little packet of tissue paper that we got billed for. Also, as far as getting the check, there is a different expectation in China. They assume you will let them know when you are ready to pay the bill. They won't come and ask if you are ready. Be ready to actively catch the attention of your waiter or waitress and say "Maidan!" (Check!). I used that phrase quite a bit while in China.
Toilets: Have you ever used a squat toilet? As a westerner, I ran across these in some parts of Japan, but they are pretty much the norm in China, unless you stay at a westernized hotel. If you haven't done a little bit of homework, it can be quite an experience. A major point to remember is that toilet paper is almost never supplied, so you must carry around those little packets of tissue paper, which also double as napkins! In one museum in Chongqing, I also found myself in the dark, as many places are fanatical about saving electricity, so the lights didn't work. A keychain flashlight was handy in this case. Wikihow has an excellent tutorial on squat toilets: http://www.wikihow.com/Use-a-Squat-Toilet