The short answer: it’s a biography.
The long answer: It’s a list of everything you know about your character, starting with his family of origin and ending at the start of your book. There are many, many lists out there for making a character outline, ranging from extraordinarily detailed to “just the basics.”
The reason you need one: to make sure you’re consistent about what your character looks like, sounds like, and acts like.
“Why? I know this character inside and out!” you say.
Sure, but like so many things, details can be forgotten. Plus if you ever write a sequel, you have a nice reference to ensure continuity. The character interview—talking to your character and asking him/her questions—can be a great way to get to know him/her.
“We’re well acquainted—I created him, after all,” you say.
True—but it’s amazing what you can discover about your character this way. A lot of this information can be mined for plot. Worth the time and effort.
Here’s my list of what you might want to include for starters in the character outline:
--Vital statistics—like height, weight, build, hair color, eye color. Here you can add in tattoos, piercings, or other distinguishing marks.
--Married? Single? “It’s complicated?”
--Where he lives—physical location. City or town, rural or metro.
--What does he live in—house, apartment, dorm. Single story or many floors? Stairs or elevator or both? Roommates?
--What he drives, and/or how he gets around.
--Where he works and what he does for a living. Consider salary—minimum wage or well-off?
--Education: high school drop-out? Graduate degree? What schools did he attend?
--Family—who are they, and how are they related to the character?
--Major formative life experiences (military service; losing both parents at a young age, suicide attempt, etc)
--Accomplishments—won a marathon, speaks fluent Japanese, makes the best chili this side of the Rockies.
--Major life ambition—climb Mount Everest, swim with sharks, get a GED.
I like to add in the character’s biggest fear, and what the character would never do. These come in handy when plotting. Of course, we’d like to make him face his biggest fear, and do what he never would do.
Two traits: serious, short-tempered, deliberate, honest, ruthless, mouthy, shy. Opposing/complementary traits are useful in putting together a pair of protagonists.
A list of favorites will help flesh out the character:
--Food (Pepsi; anchovies on pizza; allergic to shellfish)
--boxers or briefs?
--favorite movie/book/TV show
--favorite characteristics in a significant other—looks and characteristics
For the character interview, think about interpersonal relationships: family, friends, and firsts (first kiss, first intimate encounter, first job).
Here’s a set of good character interview questions from Gotham Writers’ Workshop: