To me, a portrait has controlled lighting and setting. Lighting would have brought out details of her face, especially the eyes. The bacground is a little busy for me and the white blanket distracting.
The lighting in this image isn't working for me. It's too harsh, gives a kind of creepy feel to the photo. Try shooting in natural light and note the difference in the feel of the image.
Maybe you should try putting the dog in another pose, and playing around with the composition a bit. But I like the color tones in this shot - the dog actually seems to go well with the flowers. :)