Well, the third of these four jumps out at me the most in so far as it is the poorest composed one of this little series. I find, composition went overboard with this one, and unless you care to reshoot, you'd need to crop the hell out of this one to still make it work. Sorry to sound so harsh about it. But not only is the horizon crooked, the subject is the smallest part of your frame, which is dominated by the bright sky above the tree line, loads of space around her, she being a minor event happening in some low corner, as it were. Lighting looks ok, and her smile's nice, she has something to flaunt to - make that the real subject. Not the sky, tree line, water, and all that is around her. Though I do like the leading lines given by the walkway... work with that!
The first looks underexposed though her skin might not be. I'm not fond of "up the nose" points of view, they're rarely flattering.
I'd have placed the boy somewhat further right inside the frame to give him some more room to look into.
The last one seems the most interesting, though a reflector would have helped bring out some more of his face, which now is quite dark against the very bright background. And the eyes look a little lifeless but there'd be little you could have done about that, given he looks toward what he's doing. Maybe including that into the frame would have given the photo some more life?