A few other useful tips if visiting Venice. Contact your hotel ahead of time, and ask questions about the best way to get there, dealing with luggage, etc. I found them very helpful and eager to make your life easier. If you come into St. Mark’s Square via water taxi, there are porters who will take your luggage to your hotel (for a fee). There are multiple stops for water taxis, so ask your hotel which one is closest to you.
Most importantly, wander the back streets, try to slow down and enjoy the experience. You will find some great restaurants off the beaten path, and some great shops down the back streets. There are plenty of tours available for all sorts of adventures. A trip over to Murano or Burano, makes for a nice half day trip (hint, buy the Burano glass elsewhere, its cheaper, but you do have more choices).