Can you please tell me the best way to get to Xintiandi from pudong Airport?

Oh, you can experience the maglev train at this time. Upon landing, take this train at the airport, and get off at Longyang Road Station.
Then take subway line 2 to People's Square Station and transfer to line 1 to South Huangpi Road Station, Exit 3.
After arriving, walk south around 530 yards along Madang Road.

If you want to take a taxi from the airport, the cab fare is CNY 210 to 220 in the night time. In general, it's safe to take a cab at night. Your arrival time is not too late. So don't worry.