You should direct or give instructions to model or else she does not have any idea what your photographic vision is.
By straightening her left arm she looks tensed although her facial expression is good. That is why you need to relax her by small talk..getting her to relax her shoulders goes a long way.One way of relaxing her is asking her to perform physical movements..
Walking, turning, dancing,even jumping up and down. Warming up is the key. Hair management
Has improved. Keep it up.
Ps same with moving other parts of the limbs.