Intriguing how the center of gravity seems to have shifted all to her left, and yet, if you drop a plumb from the pit of her neck, it'll pass right through that lone, supporting foot - giving her perfect balance. I also like how the background elements, like that vase in the shadow, enrich the composition without distracting from the main subject. Kudos to you and the model!
Renaissance artists called it contrapposto. The weight is concentrated on one hip, the pelvis dips to the side and the spine curves laterally to compensate, activating basically every joint in the body and creating an illusion of movement. The background seems like an echo of the model: elegant and beautiful but also just almost symmetrical with the lamp on one side and the vase on the other and the mirror framing her head. Also notice that almost all the straight lines in the picture intersect with her body and draw the eye to her.
An interesting observation, thank you .. I guess the hip and shoulder do the work .. : -)