Knowing the most popular song structures (AABA, Verse Chorus, AAA, etc) will allow you to know how to play with the form and which rules to break.

In a modern sense, AABA is by far the most popular song structure. It has two two musically similar verses and a bridge, and then it returns to another verse. Along with the different variations of this form (AABABA, ABAB, etc.), this form constitutes almost all of the music you hear these days.

Image via Flickr by Finding Josephine