#3 was a hack of a cut out :| #2 wasn't all that much better.
Though as you said it was a test so I'm not sure how much you were worrying about that.
As far as the images of the girls themselves however, you need to desaturate them just a little. Play around with the feeling of the colors, currently it looks like you just cut them out and plopped them on a background (again I know it was a test). Next time make sure you do some kind of a global effect whether it be saturation or contrast.
Just to clarify when I say global, I mean an effect that will be applied to the entire image. These generally make the image feel like it is all one part, rather than a composite. Think about adding noise (yes, adding noise) so that it is uniform across the board.