As a suggestion for photos, get closer to your subject.
This is a perfect example of where getting closer would be better - the background isn't interesting - the baby is.
To add to Mike's idea, for passing on to your sister for future pictures of this cute lady : kids are small in size, and taking pictures from above makes them smaller. She should take baby pictures from lower, as close to the kid's level as possible. I can imagine how great this shot would have been if baby had been looking into the camera when it was held near her left foot, in line of her sight.
As for the current picture, you could try cropping out most of her surroundings, to make it appear a closer shot. But you'll lose some sharpness, so up to you.