1 is the only good one. in 2, your DOF is too short and the WB is off, 3 is riddled with camera shake, and the last one has too tight of crop in my opinion.
Hi Vince, I agree that the first one is the strongest, nice job. Im going to add a NSFW (not safe for work) warning in the title, as some people may click it in whilst at work and get in trouble!
1 is the nicest, very pretty girl great eyes (I would be carefull with the whitening just so it doesnt look too processed). the last one is great too, possibly a bit tight crop or too much off around the head but it has a sense of humor with the color flag. I would have liked 3 much more if the high/back light followed up through theface (barn doors) so as you got some nice rim effect on the temple cheak area and had more of the head in, she is pretty enough to get some really nice face shots and its a waste not to use it, you could still hide most of the face but it may also have been nice with some fill in the eyes.
I think #1 is my favorite of these...the eyes are captivating (looks as though it could be a perfume ad). I love the lighting happening in #3, but it just doesn't seem 'steady' to me, as sw1tchfx said about the camera shake