Venice is divided into Sestieri, which substantially means big quarters; these are:
SAN MARCO
SAN POLO
SANTA CROCE
CASTELLO
DORSODURO
CANNAREGIO
GIUDECCA

The Sestieri are symbolically shown on the Ferro di Prora, which is the bow iron on the front of the Gondolas, whereas there are six Pettini (“combs” as usually called) on one side to symbolize the Sestieri of Venice, plus another one on the opposite side symbolizing the Giudecca island. Although San Marco and San Polo are the most famous, all the other Sestieri deserve the fullest attention as they constitute the “real” Venice, particularly Castello, Dorso Duro and Cannaregio, which is also the most populated.
The islands of Murano, Burano and Torcello are displayed within the six Pettini. A curious thing is that the top of the Ferro di Prora symbolises the Doge’s hat, whereas the space between its bottom and the first Pettine symbolises both the Rialto Bridge and St. Mark’s Basin. Last but not least, the very bottom of the iron bow symbolises the Grand Canal.
It is wonderful and highly recommended to walk around the Fondamente, Calli and Campielli of these Sestrieri and literally get lost in them (always of course with a map of Venice at hand just in case!).
Two of the fundamental things to bear in mind are the followings:
Venice requires a lot of walking to see it properly
Venice has its very own slow, unique, magic pace and to appreciate it at the fullest one should match this pace, give it plenty of time and do not hurry.