I advice a Gondola ride. It can be pricey but with the exchange rate it isn't too bad. It is well worth it. You get to see back waterways and not tourists spots.
These next two photos are from a view at the St Mark's Basilica in St Mark's Square. You do pay extra to see the top part of the church but I felt it was worth it. You have a nice view of St Mark's Square. the church is free to get in but, get in line early. There will be a long line to see this beautiful Church.
One of the things that makes Venice famous is it's masked festival. There are masks everywhere for sale. Bright and colorful. Read about the festival ever year in Venice and the masks here