Don't go to the Doge's Palace, the Correr Museum, St Mark's Cathedral, the Peggy Guggenheim Collection or any other place purporting to be any kind of cultural establishment especially the Accademia. If you want culture go to the Biennale or the Film Festival.
Equally, don't bother with Harry's Bar, the Cipriani, the Lido, the Giudecca or Burano.
There is, however, one island I went to years ago. It is a tiny monastery and has a fantastic library with real Egyptian mummies in it. It's called San Lazzaro.
Updates
Send your feedback or queries to been.there@guardian.co.uk
Search Been there
europeforvisitors.com/venice/articles/san_lazzaro_degli_armeni.htm
But as for not going to the Doge's Palace, the Correr, Basilica San Marco, the Peggy Guggenheim and the Accademia.. they may be tourist hotspots, but they're unmissable Venetian highlights nevertheless.