Cost of Living: You will be amazed at how far you can stretch your salary. You will earn more than an average white-collar worker in Beijing (5000RMB in 2007, per the Chinese Academy of Social Sciences) and much more than the average entry salaries of your graduating students. The only hard part, according to my wife, is tempering our western tastes to reap the benefits of our comparatively princely pay. You should be able to save some money while teaching here, but will be tempted by clothing, electronics, antiques, and other bargains along the way.
What a Potential Teacher Should Know That is Not Obvious #1: Mandarin Chinese, aka Putonghua. It also helps to learn some of the local dialect, as your students will tend to come from nearby your school. This is just my recommendation as I favor bilingual teaching methods. Even if you don't use mother tongue in the classroom, you should know enough to bridge students' learning somehow. Outside of the classroom, you will be challenged to use Chinese in everyday situations. While acquiring a second language yourself, you will develop perspectives that influence your teaching of English to others. BTW, once you are here it is pretty easy to find tutors and teachers to help you with Chinese.
What a Potential Teacher Should Know That is Not Obvious #2: It is very hard to find clothes or shoes for big or tall men here, so bring as many shirts and shoes as you think you'll need for the year. Once here, you can always find a tailor to customize your clothes, if you want, however.