The absolute best n° 1 to do inShanghai is simply to enjoy its skyline of beautifull skyscrapers. This is a masterpiece of human achievement and you can just sip it up

You should do so by night.

The way to do this is e.g. by chilling out at the reception of the grand Hiatt just across the world financial centre.

Just enter the building go with the elevator to the 53rd (it has only floor 1, 2 and then...53).You are not hassled, you can eat there, have a coffee/beer/cocktail across the reception or just sit down, watch outside (and inside :-) and enjoy. Best kept secret in Shanghai. Don't spread it. You atre just at the turn of the bund nice view of the TV tower and the world financial centre,

Offcourse there are a lot of other alternatives to do the same. Write them down !