If you want to visit the most interesting sights from a tourist point of view, you can move on foot without difficulties following the directions on the big yellow placards at the corners of the main streets and campi of Venice.
If you prefer no to move on foot it is possible to cover the historic centre easily choosing Venice water public transportation. The Vaporetto, the typical boats, run through the inner city.
Particularly suggestive is the course through the Grand Canal, recommended for those who don’t want to lose the marvellous palaces that overlook it. You can purchase group or individual daily tickets to travel cheaply.