Money Exchange in China is Straightforward
The currency in China is called the Renminbi (RMB) or "yuan". Changing your money from one currency into Renminbi is not a complicated process. There are a few different ways to do it, but happily, none of them involve shady characters on street corners.
Change Money at the Airport
One of the easiest and most convenient places to change money is at the airport upon arrival. Rates at all banks are the same, everywhere, so you don't have to worry about getting a better rate elsewhere. The only difference will be the charge for exchanging but this is nominal.
Change some money as soon as you arrive so you don't end up cashless at midnight looking for an open bank. Exchange counters at the airport should take both cash and travelers' checks.
One Important Note: Keep All Your Exchange Receipts!
If you plan to change any Chinese currency into another currency at the end of your trip, you'll need the receipt to do this. If you don't have the receipt, the exchange counter will refuse to change your money from RMB. So keep all of your receipts and make sure you elect to receive one if you use an ATM to get money.
Exchanging Money at Chinese Banks and Hotels
You can change money at banks in large cities as well as at your hotel. Banks will all offer the same rate that will likely be better than the rate you're offered in your hotel (although the hotel will charge more for the exchange).
Only large branches of banks will offer foreign exchange. There will be English-language signage (as well as Chinese) but if there isn't or you're confused, ask the security guard to help you. If you’re stuck for communication, just show him your foreign currency and he'll quickly understand what you want. If he waves you out the door, that means they don’t offer the service or they don't feel like offering the service (yes, that's a thing). Go find another big bank.
Exchanging Money at Hotels
Hotels usually charge a higher commission than banks do, so if you can avoid changing money at the hotel, it's advisable.
Exchange Counters and Kiosks
While these kiosks aren't ubiquitous by any means, more and more exchange kiosks are appearing throughout Shanghai at least. These kiosks look like ATMs but have a big English sign that says "Exchange". I have never tried one but it is worth a shot if you're out and about in need of cash and come across one.
Don't Go Rural Without Cash
Once you're in the countryside (meaning any smaller town), you might not be able to find a bank with foreign exchange easily. Change your money before you head off.
Bring Cash, Not Checks
Cash is much easier to exchange. It doesn't matter what they tell you at your bank at home. Yes, travelers' checks are meant to be accepted all over the world. But your banker at home has never met a surly, sleepy Chinese bank teller who doesn't feel like bothering with a travelers' check that she will have to take pains to verify isn't counterfeit. If she's in a bad mood, she'll wave you away with a mean look even though she's sitting under a sign that says "travelers' checks and foreign exchange".