The Mona Lisa
Lisa’s chest is rotated at a slight angle to the right, with the motion of turning toward her front, as though welcoming her visitor. With her chest to the right, her head is turned to the left, facing nearly toward the front, with the eyes facing directly forward. She has an understated smile in the mouth and eyes.
Her left arm is held crossed above her waist resting on a platform, fingers gently separated and curled. Her right arm rests on top of the left wrist, the pointer finger bent and touching the skin near her forearm.
I think the two most important details for replicating the position are the welcoming turn and the slight smile. The chest should be coming from the right with the intention of rotating to face forward openly. The smile should be real but almost imperceptible, with a real light in the eyes.