The Hero
There must be a hero in a monomythic story. Often, this character is from humble beginnings. This person is often an earnest, well-meaning person with many character flaws and a sense of pride.
Often this person feels a lack of direction, because their life needs to exit the comfort zone into the adventure, but usually, it takes something painful or tragic to make them finally go on their quest.
The Helper
There is usually someone on the front end of the hero's journey who helps them realize the difference between their potential and their actual current power. Many times, this person is an older person with magical powers who can give the hero something that will help them.
Consider Yoda an example of this. Also, in Braveheart, the man who asks young William Wallace what the priest said in Latin at the funeral. Both are good examples of this archetype.
The Beloved
Many times the story of the hero revolves at least in part in the longing for a woman (if the hero is a man). Many times though, the hero needs to accomplish the journey and the success over himself that the journey will entail before he is ready to be the person he needs to be for her.
The most essential version of this myth is the knight saving the damsel from an angry dragon. In other more modern accounts, though, the woman in question may already be the person's wife (or sometimes ex). In the movie Cast Away, Tom Hank's character is compelled by the thought of returning to his wife, such that he survives three years alone on a deserted island.
The Dragon
The dragon can be almost anything, but the most important part of the dragon is that it is an expression of the real enemy, which is the hero himself. He must defeat himself in order to finally best the dragon. Usually, this results in a story arch where the hero is called upon to sacrifice his own life to defeat the beast. But sometimes, this sacrifice allows for a reincarnational return of the hero, a lot like Gandalf the Grey and the Balrog.
The Home Town
The home town frames the journey. In the beginning, the home town may even spur the hero away. Sometimes the hero needs to go on a quest to save the town. Other times, he is put off course like Odysseus in the Odyssey, and the journey itself is getting home.
The function of the town in the story, though, is to show the character in his status quo, and then to contrast that status quo with his triumphant entrance after his quest.
