I know this isn't a prompt, but I use this little form to get into my characters' heads a bit when I write.
Character Name: What's your character's full name? (Nicknames can go in quotes.)
Gender: Male or female?
Age/D.O.B.: How old is s/he? When's the birthday?
Birthplace: Where was s/he born?
Occupation: What does s/he do: Wait tables at the local diner, or is s/he a full-time student?
General Appearance: What does s/he look like? I normally use this section for hair color/length/texture/if it's dyed (and natural color), eye color, weight, height, piercings, tattoos and scars. If you have a picture as reference, describe the person in it.
Strengths: What makes your character stand out? Does s/he know any languages, or does a certain personality trait keep him/her in everyone's mind?
Weaknesses: What helps your character keep from getting overconfident? Bad with relationships, way too nervous?
Likes: What makes them happy? Singing, drawing, hanging out with friends, messing with his/her siblings?
Dislikes: What doesn't your character like? Hates smokers, can't stand it when people argue... THESE ARE NOT FEARS!
Fears: What gives him/her the creeps? Is s/he acrophobic, arachnophobic, claustrophobic, afraid of public speaking...?
Personality: How does s/he act? Hyper, happy, nervous, disrespectful, etc. You can also include how certain people get treated (enemies are respected, family is everything, good with kids).
Habits: What little quirks does s/he have? Does s/he biting his/her nails, chew on his/her lip, rant when nervous...?
Other Info: Anything that doesn't fit into the other categories: Does s/he live with someone? Are there any siblings, really close friends, or significant others? Does your character eat meat?