If you only had one day to spend in Venice, Italy what would you do?  Venice is expensive so a lot of visitors stay in one of the towns near Venice and visit for the day.  What would you do if you only had a day to visit Venice?  Here is what I would do:

I would arrive in Venice early in the morning by train and would start with a visit to the Rialto Market to watch the vendors set up and the locals shop.  I would then head over the Rialto Bridge to the Doge's Palace stopping for a cappuccino and pastry along the way.  The Doge's Palace is an amazing place to visit and you want to be first in line to avoid the masses of tourists that arrive in Venice mid-morning from the cruise ships.

To avoid the crowds I would hop a vaporetto and head to Murano for lunch.  Murano is the closest lagoon Island to Venice.  If the day is nice the boat ride is beautiful and can give you a great feel for Venice and the surrounding area. 

After eating lunch and wandering around Murano I would head back to visit the Piazza San Marco.  Check the times to see when the basilica closes and make sure you arrive back in time to visit this beautiful church.  I always go at the end of the day after the toursits leave and the lines are shorter.

After a visit to the church I would splurge and pay a highly inflated price for a glass of wine or cappuccino at one of the cafe's in the piazza and sit and watch the sun set over the church.

Then I would head towards the Rialto bridge to enjoy dinner at one the restaurants that line the Grand Canal.  Check out AmoreTravelGuides restaurant reviews to find one that appeals to you.  Then I would head over the train and back to whatever town I am staing in.