I picked up a 72-hour vaporetto pass (22 euros).  It was a good value and convenient as I jumped on and off the vaporettos frequently.  The system is easy to learn.  Once at the "bus" stop, look at the arrows pointing in the direction in which you want to go.  Not every line stops at every dock, so be sure to know which line number you need.  I did not bring a map with me and used the one the hotel provided.  The city is built as a maze, and even with a map I had difficulty figuring out where I was at times.  Next time I'll buy a map that includes hotel names as there appeared to be a hotel on every street and they would work well as landmarks.

When using the vaporetto pass for a specific time period, do not punch it in the machine -- just have it with you.  The system is on an honor basis -- just don't get caught without a ticket.  Twice there were officials aboard checking.

Learn where the major destinations are (San Marcos, Accademia, and Roma are some) and follow the signs with arrows.  You'll come across at least one of these signs at every square.  Don't be confused with signs that have arrows pointing in two directions -- not puzzling really -- it just means you can take either lane to reach your destination.

Grand Canal