Minor characters are often the neglected heroes of fiction. If the protagonist didn’t have other people with whom to interact, most stories would fall apart pretty quickly. So, whenever the need arises, we stick in a taxi driver or a receptionist or a bum on the corner. Often, these unnamed characters fulfill the needs of the moment, disappear from the story, and are never thought about again by either the protagonist or the readers. This isn’t necessarily a problem, particularly since you don’t want a bunch of dead-end characters cluttering up your story and getting in your hero’s way as he attempts to get from Plot Point A to Plot Point B.
We need to realize, however, that this nameless, faceless multitude of minor characters presents a wonderful opportunity for bringing depth and memorability to our stories. David Guterson’s East of the Mountains offers an incredibly complete cast of characters. Every person in this story, even those with the shortest of walk-on roles, strikes the reader as a complete human being. We never doubt that Guterson’s protagonist is surrounded by a world of living, breathing, three-dimensional people. The minor characters in this story don’t just serve to push the plot forward in necessary ways. Every single one of them leaves his fingerprint on both the main character and the reader.
The key to achieving complete minor characters is to envision them as complete people—and not just cardboard cutouts to fill the gaps in the plot. Every person has a story; every person has a life that extends far beyond his interaction with the protagonist. Each minor character is unique and detailed. We certainly don’t need to share each and every minor character’s life story with the reader, but if you keep their back-stories in mind as you write, you’ll end up with a rich and varied supporting cast.
Tell me your opinion: Do you have any minor characters you could flesh out a little more?
Don't just answer me, answer her too, and while you're at it, check out her video on the subject - http://wordplay-kmweiland.blogspot.com/2011/01/make-most-of-your-minor-characters.html