Holy crap, you're doing this for free? I've seen artists who put much less effort into their work charge for this sort of thing; this is really awesome of you! I guess I'll have to jump on this deal:
Reference image?
For overall appearance, as well as hair--
What color are their eyes, skin, hair, lips, etc?
Orange eyes, olive skin, bleach-blonde/white hair, skin-tone lips. Ata is a character first and foremost of Egyptian blood, yet European influence has caused her features to resemble more of a mixture of the two genetic cultures.
What hair style do they have?
I know hair's kinda iffy, so feel free to take artistic liberty with what you think looks good; but short hair is best hair.
What build do they have? (Muscular, thin, thick, etc.)
Lithe (thin), with muscular undertones beneath the slenderness.
What is their gender?
Female.
Make-up?
Caked on to a degree of almost another layer of skin. To a distant onlooker, Ata would seem to only be wearing light eyeliner/shadow, yet closer examination would lead to revealing an almost bronzed hue of camouflage for her imperfections. [If you want, since this is a close-up, add subtle scarring beneath the makeup.
Accessories?
I would say earrings, but her hair would probably cover her ears. That being said, she -would- have a black stripe of fabric around her neck-- not all the way up to the chin, more like a collar than anything else.
Now, how would you describe the overall appearance? (Nose shape, jaw shape, lip shape, eye shape, etc.)
In one word: Refined.
In many words: Combining a European father with an Egyptian mother is an exercise in genetics, but I think the end result is fairly simple. A roundish face, with a sharp nose and slightly slanted eyes.
What do you want them to be doing?
Imagine the look the most snotty, stuck-up girl you know makes when someone says something she's disgusted with. She wouldn't wrinkle her nose, God forbid she creases her face at all, but she shows the utmost disappointment in whatever crass thing someone had said to her. Shoulders tensed, recoiling away slightly (chin to the left, eyes looking right style), clearly displeased.
Background?
None needed, translucent works well, but a slightly faded golden outline would work as a base.
Extra Comments/Side Notes?
Have fun! Your style is awesome, and any creative liberties you take are fine by me.