Hi, I will start Hangzhou day-trip from Shanghai (round trip), can you please advise the trip route?

Take a high-speed train at Shanghai Hongiao Railway Station to HZ Station in the morning. Upon getting there, take bus no. 7 or Y2 to Lingyin Temple. After that, still take bus no. 7 to Broken Bridge to see the West Lake. U can take a boat for sightseeing or rent a bike to tour on your own. Afterwards, you are suggested to take a taxi to the Six Harmonious Pagoda for visiting. Because your wanna get back to Shanghai on the same day, go back to the train station early.

I also heard the Shanghai Tour Center arranges one-day trip to HZ from/to Shanghai: bus fare, and entrance fee for the attractions are included. But not sure if you can access one on your travel date. Anyway, try to consult by yourself at this location:
No. 2409, South Zhongshan 2nd Road