Photographing people is much easier than photographing dolls because humans can change their facial expressions. Photographing Sasha and giving her some emotion and attitude requires a bit of trial and error as well as an eye for what works and what doesn't. While light and shadow help to create a mood it might take a particular tilt of her head to create the attitude needed to convey personality and contribute to the storytelling of the final image.
To begin, the top photo is rather flat which might be OK for a passport but not very interesting as a portrait. The image just below it has soft shadows added (by moving the light source) which adds some dimension to the overall image.
Glamour and fashion photographers usually shoot from just slightly above the subject's eye level and always make sure there is a nice defining shadow under the chin whenever possible.
The rest of these photos were taken with the same lighting system. The differences in shadows and lighting is created by changing the position of the head. Since each Sasha has a distinct personality it might take a number of poses before her character emerges. But patience and persistence will eventually discover her attitude and unique personality.