The chubby and food-loving Sancho Panza, in combination with the spindly and absurd Don Quixote, make an intriguing pair. The whole two books of Don Quixote are, in essence, a situational comedy of these two men going about and interacting with various types in the countryside.
Throwing two dichotomous characters (or three) together into a stressful situation, or bonding them through some unlikely chance (a joint inheritance! a sudden ambush! a newly-discovered common enemy! an irrational love of all things chintz!) creates the opportunity for you, the author, to make an impelling draw on the reader’s curiosity.
If the villain and the ingenue genuinely fall into sympathy with each other, we want to know WHAT WILL HAPPEN NEXT?
This also creates the potential for incredible comedy. If, for example, the young lady is frequently in the company with the villain (you know, because they are the only ones who were touched by the Alien God Grazza, and therefore must work together to protect the planet), and the young lady has a previous attachment to the young hero, how does the young hero react to this situation? Is he outraged? Does the hero become best friends with the villain? Does the hero change into a villain as well, or does the influence of the ingenue reform the character of the villain?
Exploit unlikely types; the reader is familiar with common types, and will be impelled, almost against their will, to find out more about your story. Because, after all, HOW COULD YOU POSSIBLY RESOLVE THIS PAIRING? OR CREATE A COHERENT STORY?
THE READER MUST KNOW!
When you’ve created an urgent NEED TO KNOW in your reader, you’ve entered the realm of word-of-mouth and potentially large sales.
Make a list of character types. Now choose the two types who are the worst possible, and least workable pairing. And, go. Bonus credit if you can make them fall in love with each other.