I would recommend not going to Beijing specifically, while their congress is meeting because they would restrict foreigners gathering numbers and post military around town. Also remember, there is no freedom of speech there, so be cautious about what you say.

In big cities like Beijing it can get pretty expensive to go out depending on where you go, but in more rural cities that are only one or two million, it can be a lot less expensive to eat out. The embassy section of Beijing is interesting and beautiful and may have more foreigners, though I don't recommend stopping and lingering in front of embassies. Keep moving, especially if it's being guarded by the Chinese military or something to that effect.

The taxi drivers might try to rip you off.

Prepare for lots of horn honking, but that's simply how they signal in some sense, they aren't mad.

Chinese are very practical, and some can be very helpful. Others will lie to your face or try to con you, to keep your street smarts on alert.

It's a big, interesting, amazing country. Enjoy it!