During narration, at what point do you take time to develop your character? While it would be nice to open or interrupt the story to give the reader a good sense of people you're writing about, it's not always possible. On the other hand, developing the character throughout the story may leave the reader lacking critical understanding your participant's behavior or traits. Granted, the situation will usually determine the amount of time you can spend with the character without detracting from the story's flow, but what's the minimum? Describing just enough of the character with the intention of revisiting him/her/it later in the story may not always be the best approach. Consider for a moment a character with some very unusual trait that will become key later on. While the behavior is not related to the action at the moment, would you toss it in early to make the actor memorable?