I go to China a few times a year, in fact I'm headed there again next week.

What part of China are you going to? If you're going to be in one of the main cities, then you really have nothing to worry about. They are just as modern as any city in the US. Even in some of the smaller areas, it's not that bad. Violent (confrontational) crime isn't that common over there, what you proably have to worry about it stuff like pickpocketing or scams.

Sanitation is probably the main concern. Always carry TP and some hand cleanser, and if you have a sensitive stomach, it's recommended to only use boiled water when brushing your teeth. Some of the hotel will keep thermoses of boiled water specifically for that purpose. I dunno, I use the tap water and I also eat from the street vendors, and haven't had a problem yet (knock on wood).

Other than that, just take the usual travel precautions and you'll be fine. If you've never been there before, you might have to get used to their customs, they may seem strange at first. For one thing, people in China don't really wait in line, you just form one large group and shove your way to the front. That's just how it is, you'll get used to it.

Also, they tend to have much smaller personal boundries, meaning they will get up much closer to you when talking, or just standing around. People from the US probably aren't used to it, and it makes them uncomfortable.

And if you go to the street markets, especially touristy ones, the vendors are very, very agressive, probably the most aggressive ones I've ever encountered anywhere. They will literally grab people by the shirt and pull them back to the stores, or follow them down the street trying to make a deal. If you ignore them they will eventally go away.

Spitting on the streets used to be a very common practice there, but since the Olympics they've tried to curtail that with signs and warnings. Still, a lot of the older generation is just used to doing it, so you'll probably see people still spitting around you.