Another element of the storytelling aspect of a photograph is the presence of cast shadows. In the adult world, photos are full of cast shadows that add dimension to any image. In the world of dolls cast shadows are just as important to creating a sense of space and reality.
One good trick is to use a "presentation board" -- a three-fold cardboard background that can serve as a wall or corner in the photo. They are available at stationary stores or it is easy to create one.
Looking at the top photograph you can see a faint vertical line behind Sasha's head that indicates the corner she is standing in to create this type of cast shadow. The other images were created by moving the wall closer or setting it at an angle from one side or the other. No matter how you position the board a cast shadow will help to create a sense of dimension and reality.