Nice work; C&C per req:
1. Nice pose, but somewhat under-exposed. Judging by the light on the trees you had a bright background. Some diffuse fill light about about knee-level aimed up would have evened up the exposure nicely. I'd suggest a slight levels and curves, and perhaps a wee WB adjustment.
2. Nice idea, but I think it would have been better to have it held out further from the body; there's a bit of cuff which is slightly distracting to image right.
3. Nice pose, great expressions, but your conversion is overly mid-tone rich. There's lots of grey, but precious little black or white. Again I'm thinking the bright sky played with your exposure. When shooting this kind of one-chance only scene, it's always best to shoot a grey card for exposure reference and a white one for WB reference (You can use a grey for both, but I prefer to shoot one of each).
4. Nicely done, just a touch under-exposed.
5. Good.
6. Again good pose, but see comments for #3 re exposure and conversion.
Overall, you've got some really nice poses, but your images are suffering from exposure issues. As I mentioned frequent use of white & grey cards will help minimize many of these problems, as will the use of fill-lights and/or reflectors to even up exposures. Also try and avoid metering areas with bright highlights (#1) as these tend to play havoc with matrix/wide area metering.
Just my $00.02 worth - your mileage may vary.
~John