OK here's my 20 cents worth. I'm also not really qualified to comment but hey, you put 'em up here!
For me number three is the best shot, it says something. The downcast eyes and hint at
modesty, or mystery. The toned down colours also help set this mood. Would a hair light help to bring out a bit more contrast to the image.
Number two is interesting and for me a totally different sort of shot. The look is very stark and 'in your face'. Maybe harder edged lighting and a background that's much darker might make this more sort of shocking.
Number one would be helped I think if yo could see the face, even just a hint of it would add interest.
On reading the postings above, there's heaps of ideas to try, good luck.