The best teaching jobs in China are at International Schools. These schools teach in English according to the American or British syllabus. They usually require a full teaching qualification equal to what you would require if working in the UK or USA. They do however pay roughly equal to what you would get working in the UK or USA. So this is typically the highest paid teaching job available.
There are thousands of small private schools around China. These teach kids after school. Parents spend a lot of money on ensuring their children succeed and so these private classes are big business. Teaching qualifications are usually not required but a degree of some sort or other in any subject is essential. Pay will vary depending on the city and the number of hours you work. These school will ask you to work every hour possible as they try to get their money’s worth out of you. Some small private schools might be less than trustworthy. They are known to cop-out of some aspects of the contract such as failing to pay your airfare at the end of the year. Also, it is not uncommon to find that they are unlicensed and have employed you illegally – which will land you in trouble with the police when caught.
All Universities and many larger state schools also employ foreign English teachers. They tend to not pay as well as the other schools mentioned but they provide better working conditions. Usually, your work week will be just 15 hours. They will provide accommodation and include you in various school activities. Also, because they are government institutions, you will be treated fairly and you will get all the contracted benefits paid.