In preparation, some writers outline their main characters in almost excessive detail -- down to their favourite colour, song and food, and whether or not they clean the tub after a bath. If nothing else, this premeditation saves one (in the middle of chapter five) from staring at the screen for forty minutes while one tries to decide on a suddenly significant/useful mannerism or minor fact.
But sometimes, one receives the impression that writers are so entranced with providing a full-frontal of their major character(s) that they neglect the minor ones.
While they seldom require equivalent depth, secondary characters should not appear as cut-out dolls or mechanical pieces. Certainly their prime use is to provide information to advance the plot, motivation for the protagonist, or revelations about the lead character, but they are most effective in these respective roles when they live.
Of course, one has to guard against over-development of minor characters, else they may disclose an alarming tendency to run away with the story.
Jason's Clarity of Night flash fiction contest closes tonight at 11 pm.Wildly popular. Last I looked he's received 200 entries. Fascinating reading and tremendous variety. Counters winter blahs and seasonal ennui.