"How do you get a visa for China?"
The best thing to do is to get your visa before you arrive in China. Unlike other countries, such as Cambodia and Thailand, you generally cannot get your Chinese visa at the airport. And sometimes it can be difficult to get, depending upon what country you're from. Getting China visas from the US can take some time, sometimes upwards of three to six weeks. A good travel agent with the proper connections can usually cut that time period down significantly. It's always best to get your visa before you leave, and try to get a sixty or ninety day visa. Visas for longer durations are generally not given out unless you plan on attending a Chinese university. You can extend you visa, once you are in China, with the right reason (e.g., attending school), at a local Chinese police station.