On Average full-time English teachers make 8-15,000 RMB/month in SH. Hourly wage is around 150 RMB per hour. If you work part-time and put in the hours you could make 20,000+ especially if you hook up some Business English classes which can pay 180-200 RMB + per hour. You can earn 25,000+ RMB in the international schools but I understand you need to be a qualified teacher (not just ESL) with at least two years experience.
If you look for a job locally and have little or no experience it is very difficult to secure a position that is better paid than English teaching. Believe me I've been there! Best to work for a company back home and look to get transferred. You can check the jobs on this site and
http://shanghai.asiaxpat.com/careers/. If you have just graduated and/or only have a few years experience and are prepared to accept a job with a small/medium sized company for around 10,000 RMB per month at best then go for it. But if your looking for a position with a Fortune 500 company it seems that the vast majority do not recruit foreigners actually in China (unless of course you have a lot of experience or some unique skills). You may be able to find something with a small trading company, real estate agency, etc