C&C per req:
1. This is a nice, happy picture. I like their expressions, but the exposure needs some work. I would have tried for at least one, and I think two more stops of fill light here so that I could boost my shutter speed up and eliminate the blown highlights on her shoulder. I would also prefer to see a wider crop so that her arm wasn't cropped that way. If you need to, cropping limbs is fine, but NEVER at/through a joint, and NEVER, EVER bisect them laterally!
2. This is a very nice portrait, unfortunately, having shot it at ISO 3200, it's very, very noisy. This is a case where a couple of strobes to supply the lighting to get your ISO down to 100-200 would have taken an image from nice to outstanding!
3. Assuming the green cast is simply a hosting issue, this image is nice, but that's about all. It really doesn't look like much more than a casual snapshot. I think a tighter crop and a much shallower DoF and less cluttered background would have helped immensely. Remember that when shooting with wide glass (such as 18mm) you have vastly more DoF than does longer glass at an equivalent aperture.
Just my $00.02 worth - your mileage may vary.
~John