The lighting of the background and the baby and the fairy are all different...This is especially noticeable on the baby's fingers, which are in shadow as they grip a barrel lit from the side...Consistency counts.
Also, the flowers on the baby's head look extremely cut an paste, with a dark line on the bottom. You might try a bit of the Dodge tool to lighten the bottom, and slightly blur the outside edge of the flowers to help them better blend with the image.

This is how I like to get my babies clean... (see I am allowed to say that and it is definitely not creepy because I in fact do not have children, so it's fine and not weird at all...)

the fairy looks very "Disney-like"

should make fairy facing with her back to us (facing the baby or side view of fairy),
now don't look right yet

a bit of lighting on the baby to match the background lighting and some shadows and this could be a good work