How do you audition characters?
It's strange, now I think on it, how when I was a kid I used to make up characters all the time, lists of them with different characteristics down to their favorite color, but they never did anything, they just had traits. Were traits.
Nowadays I usually assemble traits as I need them during the process of writing--does Joe need to express some angsty emotion? How about I give him a dead relative? Do I need to specify what kind of dead relative? Sue needs to obstruct The Heroine by refusing to take off her shirt. Because she has a tattoo of Donald Duck on her breast?
But that is all after the characters have shown up, auditioned, and signed up for their health (or lack-of-health) benefits.
I don't think I've ever mentally "seen" a character before he or she had a personality.
Rarely, I come up with a name first, and then think about what a person with that name would be like.
Lately, characters seem to form out of plot roles I need filled. I think about who might fill that role, and why, and what they'd be like--what do they want?--their name and appearance comes later. Sometimes I hand out their initial traits randomly, or to go against stereotype--say, I need a rabbi. Okay, he won't have a big white beard, he'll be younger than you expect. And tubby rather than ascetic. Pretty soon, the character feels real to me and I can write them more intuitively.
Another trick is, what's their secret?
If I feel lazy and need a set of traits already assembled, a few times I've gone to a baby name book I have that includes little essays on the personality types associated with astrological signs. I adopt one of those types more or less wholesale, perhaps with a little switcheroo here and there to go against expectation. Then I start wondering why that person would have those traits, what they want and what they need, and once I start wondering why, I'm golden.