Overall I think you did a wonderful work on the photography. The lighting is great, really offsetting her skin and making her appear to glow. I also appreciate the fact that you didn't pose her in something more provocative, or nothing at all. I know plenty of guys might disagree with me, but sometimes it is best not to see everything to make an impression. For that, I'd like to give you 4 and a half stars on your technique.
Originality I'm giving 3 and a half stars based on the fact that, well, girls in bathtubs isn't out of the ordinary. However, I'll give the caveat that I prefer it. Something doesn't need to be original to be beautiful. Vision I'll give 4 stars, primarily because I believe (subjectively) that you had one in your mind, and executed this shot with minimal background clutter.
The overall impact I'm giving 4 and a half stars due to the fact that combined with your own photography work, the model you chose is stunning. Very classic face, high cheek bones, amber-hued brown eyes and brown hair. Perhaps you could have gone with leaving the hair less wet, but then again that is me being subjective on the matter.
Overall, a very exquisite woman with an excellent photographer's eye makes for a wonderful shot. I would give your 4 to 4 1/2 stars overall.
The picture balance is just okay but I'll get to that in a few sentences. The lighting is nicely balanced and even. I really like that there is no distraction from the model (as in other distracting colors in the shot). The tones are excellent. Something about the crop I'm not crazy about. I might have moved this shot to the left and up about 6-8 inches so her whole head was in the shot. But I like the aspect ratio of the pic. You could crop out the knee and it would still be wonderful. I don't like the grey pipe in the shot and would have probably ps'd it. You asked for criticism on this so I gave it a shot...In all honesty I probably couldn't compose half as good a shot under the circumstances. Cheers.
Say Grace...i don't know if i can before i can jump on her like the food on the table....XD....i have no time for Grace right now. I'am hungry.......she so gorgous i can eat her up........ Being pretty is so vanity...thats what making choosey dad choose grace over jif the peanutbutter.......i would too. She another fabolous cutie...great skintone...i wonder if she tans in one of them booths like SuperMan....hahaha. Only thing that would set this off too...if she had them cat eye liner make-up on......i woulda danced like it wasn't going to be no tomorrow...and i don't dance much...XD.