If it's your first serious attempt at female anatomy, you're making it very hard for yourself by not only attempting to
do it, but also pixel it on a pretty large canvas, and then douse it in complex texture and colour work.
I recommend just doing anatomical studies with pencil and paper, or a tablet, and learn the basic 3d shapes. If you just sit a reference next to you and start copying the contours and basic shadow shapes, you're taking the long... loooong road to learning figures. Learn how to capture the gesture of the figure, then fill it out with basic construction, then detailed construction from more extensive study of skeletal and muscular systems. Once you feel pretty fluid with that... then you can make the crazy bird lady (which is wonderfully colourful and interesting, don't get me wrong).

Start with basic solids (I start with a simplified ribcage and pelvis), work out the spine curvature, then build the forms up. Once you have your forms you can establish your planes and lay down your shadows. Sorry, don't think the edit demonstrates it very well.
