Stupidity'sUnglyHead, that's deep yo, Another suggestion or way of saying it would be rather than thinking of it as just a photoreference, realize that somewhere it is real, and in three dimensions, what does she look like from the side ,immerse yourself a bit into your work. This may assist you a bit in adding depth to you peices.Also, shadings tools work well with graphite as well. you could also add a dark background this will highlight the subject without the need for too many lines. and again, shading tools work well for the softening of lines.
~"With a little hope, and alot of try, anything is possible."~
~"The harder You work, the better life gets."~
~"The pain doesn't last, but the gain will last forever."~
~"Fear is my courage." ~Mr_S_14