what is the best way to travel from Baoding to Shanghai?

No direct train or flight runs between these two places.
Only one direct long-distance bus from the Long-distance Bus Staion is scheduled at 08:40.

Or you can take the bullet train from Main Railway Station, and go to Beijing South Railway Station.
The train schedules are 08:43 and 13:21. It take around 1.5 hours on the way. Then transfer to direct high-speed train to arrive at Shanghai. They depart from 07:00 to 21:23. The duration is about 6 hours.

I'd suggest you take a high speed train to Shijiazhuang. Then fly to Shanghai within 2 hours.