You've all heard of Joseph Campbell's Hero's Journey, made popular in interviews with Bill Moyers, but have you heard of Canadian critic Northrop Frye's theory of myth, elucidated in his Anatomy of Criticism?
Frye holds (as does Campbell) that myth is the basis for all literature, and all literature can be categorized as one of four archetypal genres or mythos: comedy, romance, tragedy and satire. Further, he associates each genre with one of the four seasons, sharing the cyclical nature of seasons. Moreover, each genre can be merged with its adjacent: thus comedy gives rise to comic romance, romantic comedy, comic satire, satiric comedy, and so on. Each archetype gives rise a different relationship between the hero and society. For instance, in comedy, the movement is the hero's integration into society; in tragedy, his expulsion from society. In romance, the audience identifies with the hero; in satire, the audience looks down on the hero.
Further, the hero of each genre moves through six phases, literary structures which can be derived from each mythos-- moving from innocence to experience, from fantasy to reality--but the hero experiences each of them differently, colored by their their genre. In each phase, two of its structures are influenced by the preceding season, two by the succeeding season. There is a downward movement toward tragedy, an upward movement toward comedy
All this may seem a little complex, but it's really quite elegant, describing the general shape of, well--every--story. This is not meant to weigh you down, but to gives you the tools to satisfy the audience's genre expectations (which are bred in the bine) or to subvert them.
Perhaps a diagram will help, Luckily, I happen to have one handy.
You can see, for instance how in the third phase of comedy, the young hero is triumphant: how romance evokes the quest theme, how the hero finds victory in tragedy, while satire engages the victory over common sense. The book is rich with examples of each of these phases.
Again, this is analysis of what has gone before, not a prescription for your next project, any more than music theory should get in the way of writing a song. Study of structure is meant to reveal, not to hamper. If you have any questions on this admittedly incomplete summary, just leave them in the comments below, and I'll try to address them.