With the female face, try to keep the contors smooth and round. The jaw line more soft with the nose generaly smaller than a male.
When doing the mouth try not to draw the mouth on the face but rather sculpt it into the excisting geometry. Go realy low Sub D level and use the move tool to get a basic upper and lower lip, your need wire frame view on for better visability.
It will look very rougth but will set the edge flow up for higher Sub D levels. ON your model I would bring the lips slightly back and the whole nose forward. Add more volume around the lower cheeks and face and try to keep the space between the eyes as wide as a eye width, do this by moving the inner eye only.
Each Sub D level work the whole head including the ears if yu do this, then by the time you get to level 4 your model will look complete in form and detail.
I use the move tool alot with a large brush and will help a great deal. Here is a video I did a little while back sculpting the whole female. Watch how I start with real low sub d level and how the face form starts from me using the move tool. If you like I can pose some picture exsamples to help with the female form for the face.
http://www.veoh.com/videos/v1309656TMG6y2GQ?c=CGDreams
And here is a link I found helpfull.
http://www.virtualffs.co.uk/male.female%20facial%20differences.htm
P.S, looking much better now.