Recent shoot, some C&C.
First one: I like the tonality of the BW conversion and the pose, but I'd be tempted to crop just below the elbows. I think that makes the portrait more intimate - i.e. makes me feel like she's looking directly at me and it becomes instantly more engaging. The lighting works too but I'd probably lighten her left cheek just a little around the cheekbone.
Second: Colour works for this one and the matching outfit, nails and lips make it much more interesting. You've got the sideways glance nailed but I'm not sure I like seeing up her nose. Again, I think a slightly tighter crop would work here - or wider. i.e. either you need to get her left hand fingertips also in the frame, or crop tighter to lose the hand altogether.
Third: Too dark for me, there is not enough light on the model's eyes and the "V" of the elbow on the left side is too distracting.
Fourth: I like this one. not all girls have tatoos like that so I think it should be the focal point of the photo. I'd have wanted more light and sharpening if necessary to really show it off to the fullest extent. There's also a distracting thread sticking out of the dress at the back (nitpick I know). It looks like you might have done some dodging on the eyes, but I think you could ahve brought out the colour more to make them stand out. Her complexion also looks a little err... muddy? I'd have tried some smoothing on the skin and also cloned out the spot in the middle of her chin. A touch more saturation on the lips wouldn't go amiss either.
Last One: My favourite by far, you have nailed the pose, the lighting works well for most of it. If I was to nitpick (again) I'd consider putting her right hand on her thigh or hip and with her left you could try either having it by her side (to hide it) or perhaps having her fingertips visible through her hair. By virtue of the vingetting at the corners, it does focus us more on the subject (which I like) but it also makes her legs look almost pointed where the knee is. You could have her raise her legs and get them in the frame too perhaps? There are all minor comments - I really like this one...