what is the best way of going from SZ to Zibo and then to shanghai

Does the SZ you mentioned refer to Suzhou?
If so, in Suzhou North Railway Stations, there are bullet trains to ZB. You can take one and the travel time is about 4 hours. Then to Shanghai, you can also take a bullet train to Shanghai Hongqiao. The train ride is about 5 hours.

sorry, it refers to Shenzhen

Oh, there is a train K1688 from Shenzhen to ZB, leaving at 10:50 and the travel time is 30.5 hours. If you want a fast way, just take a plane from Shenzhen to Jinan first. In the Jinan airport, there are direct buses to ZB.