Some thoughts: (Refering to images L->R, top->bottom) #1: There's great potential here, but for me, the tight crop has ruined it. If you'd opened it up a little more such that his right arm/elbow was fully in the image and the little bit of his left hand wasn't cropped away, this would be outstanding. In #3, again the "little bits" you've cropped away (left forearm, right finger-tips) really hurt the image.
#s 5&6: When using such strong leading lines as this walkway, try and place your subject at the vanishing point, not off to one side. As composed, my eye follows the centre span of the structure right past the model.
#12: Up the nose poses are rarely attractive, and this particular crop makes it seem like her breasts are the main subject of the image; a higher shooting position and lower crop would have helped.
Just my $00.02 worth - your mileage may vary.