I haven't been to Guangdong myself, so can't tell you that much about the place itself.
As for China in general, keep in mind that most people do not speak English. Taxi drivers also sometimes struggle to read Chinese adresses written in Latin script. Therefore when you wanna go somewhere it's best to have the staff at your hotel write the adress for you in Chinese characters. And the retun adress to the hotel!
Chinese people are not big on physical intimacy, so try not to touch anyone without their permission. Do not suddenly hug or grab people -even friends- without warning.
In the cutthroat capitalist world that is today's China, people are easily upset and arguments are common. Try to avoid getting into those. Physical fights are very uncommon, but verbal arguments can go on for hours if you get them started.
Talking about politics is...not forbidden, but I wouldn't encourage it. Chinese people only tell their real opinions to people they trust. If you're a stranger asking about sensitive stuff they will just tell you the official line they learn from the media, and also start to view you as a bit of a threat. Wait until you get to know someone a little before going into this territory.
Chinese people are very curious and will ask you questions about things that in the West are considered private, for instance if you are married or how much money you make. If you don't feel like telling you should dodge the question in some diplomatic way since giving no answer at all would be a little rude.
Chinese food culture is very liberal and includes all kinds of things. If you're a Muslim and want to be on the safe side you will want to look for the Halal resturants that the Hui and Uigur ethnic groups run. They usually have green signs and the word "Halal" in Arabic text.
Other than that I think you're probably intelligent enough to recognize obvious scams. If total strangers walk up to you and adress you in English it's usually the lead-up to them trying to get your money in one way or another. Just walk away.
Shops that are permanently located in some kind of building usually have fixed prices now. Sales stands in the streets though still allow bargaining. If you wanna go for that or not is up to you - I usually stay clear of them since I suck at bargaining.
Younger Chinese men can appear a little feminine when speaking in English, since they are shy and uncomfortable outside of their own first language. Some foreigners wrongly get a kind of homosexal vibe from this, but I assure you that in most cases it's not - don't panic!
China is a lovely country and I'm sure you will have a great time if you observe the above precautions.

"Positive" advice:
-See the sights.
-Make friends with the locals if you find younger ones who speak English.
-Try the food as far as your beliefs permit.
-Try to learn a few words of Chinese, or even characters.