From April to November are the best months for traveling through China. Outside of those months temperatures can fall well below 0 degrees Celsius, especially in the north. The ideal months are those of spring and autumn: April-May and September-October. Many China Tours focused on the south where climatic variations are less severe. Beijing experiences very cold conditions in December, January and February. On the far north western reaches of the Silk Road, it can be extremely cold from October through to March. July and August are very hot and dry in these regions. Tibet experiences cool weather year-round and travelers should prepare for four seasons in one day.

Apart from calling IDD from your hotel room, there are various phone cards available in post offices inside hotels or at most newsstands on the street in China.

Among them IC card and IP card are the most popular ones. Most public telephones you see in booths are IC telephones, which allow you to call home directly. IC card is issued by China Telecom; international calls with IC telephone cards are relatively expensive, usually over 10 RMB/M. When you buy an IC card and want to call back home, simply just find a telephone booth either in hotel, restaurant, airport or some other places, insert the card into the phone, follow the vocal instructions to dial the number you want. 

IP cards are issued by different issuers such as China Telecom, China Unicom, China Netcom and China Jitong, thus the Rates for international calls are different. China Unicom's rate for calls to Hong Kong, Macau and Taiwan usually is 1.5 RMB/M, 2.6 RMB/M to America and Canada while 3.6 RMB/M to other countries. The other's rates for international calls are either a little bit higher or lower than that of China Unicom. Currently, the IP phone service has covered the whole country, providing international service between China and over 200 countries and regions. There will be instruction on each IP card to tell you how to make a call, you can use the hotel phone to call with IP card and the hotel usually will charge some fare as that of city call. 

Please note: some of the IC cards or IP cards can be used only in certain provinces or regions, so please check it and also the expired date before you purchase them.

In China, GSM networks operated by China Mobile provide coverage in every major city, while CDMA network run by China Unicom is improving its coverage, so if you have a dual band or tri band mobile phone or use COSMOTE card, then you can use your mobile phone in China in most big cities, though any calls you make will be considered long-distance. A cheaper option is to buy GSM SIM card, which is a telephone number. There are mainly two kinds of prepaid cards you can choose: Shenzhouxing issued by China Mobile, Ruyitong issued by China Unicom. You need to finish using that amount of prepaid charge before indicated date. You can buy charging card in amount of 50 RMB and 100 RMB to recharge in post offices, stores and newsstands easily.

P.S. 
The following is how to dial international call from China:
00+country code + region code + phone number
The country code for USA and Canada is 1, 44 for UK, 61 for Australia, 43 for Austria, 41 for Switzerland, 852 for Hong Kong, 39 for Italy, 31 for Holland, 64 for New Zealand, etc. For the other countries, please check the instruction book in the hotel room.

You can use the Internet service in the business center of the hotels; some rooms of certain hotels have the internet access, in which you can use your own computer. And internet cafes are a booming business in China and you should have no difficulty in finding one in cities, big or small. Besides, many cafes and restaurants in China provide free Wi-Fi – you may surf the internet easily on your smart phone there.

As China continues to open up to the outside world more and more people are learning English. In 5-star hotels, most staff can speak moderate levels of English. However, on the streets and in local restaurants very few people can speak English and street signs and menus are mostly written in Chinese characters. With the help of local guides and tour leaders these communication problems are easily overcome.

In china, each city has its snack of local flavor. Normally it is not included in the tour group program unless you have the specific request. If you have interest, you can ask the local guide to make arrangement for you. But you have to pay for the snack and the bus transportation. You can also go by yourself. Before you go, you can consult with your local guide and she or he will give you suggestions on what to eat and where to eat. Also you can follow-up the travel guide book's recommendation. 

International credit card is only accepted in large hotels. For most of the restaurants in China, Cash in Chinese Yuan is acceptable. So bring some cash in Chinese Yuan before enjoy your meal.

Here are some delicious snacks in Chinese major cities In Beijing, Peking Roast Duck, Mongolian Hot-pot, Imperial court cuisine, Tan-style cuisine
In Shanghai, Din sum dinner
In Xi'an, Tang Dynasty dinner and show, Dumpling dinner
In Guilin, Tea food banquet