Rob said:Ah-ha, these pictures I recognise from General!
#1 Generally a pleasing image, although there are a few things I believe could be improved: The amount of extra space in the frame. Do the tree branches help, or distract? The contrast of white sky and black branches make it a bit cluttered. Personally, I would have tried to gain a bit more height advantage over the subject to decompress the angle of her, the branch and her arm. Actually I think a square crop would work - the subject and branch aren't really portrait or landscape aspect. Also, a little fill flash can help balance the light between subject and background.
#2 Good idea for a pose, but it's a portrait aspect shot - i.e. should have been vertical to maximise her presence in the frame and minimise that nasty white sky/branch combination. It's worth bearing in mind that people have a natural squint when looking at near objects and this becomes apparant when there is a lot of eye-whites showing. As I mentioned, the black point needs adjusting. Let me know if you want me to have a go in PS and post what I mean to show you?
#3 Good shot (in colour). There isn't enough tonal separation from the background to do B&W effectively. I'd have liked it more with her eyes open/looking up, or something... just something slightly wrong that I can't pin down.
One thing to possibly consider is a gold reflector. This adds about 1/4 as much light again to the subject gently, cancelling out unwanted shadows and gently warming the subject. I'm a big fan of reflectors and they are a very underused photography tool. They are also cheap and don't need batteries!!
Overall you've got good captures, but they lack some polish, especially regarding the lighting and composition. Work out those two and you'll be winning in no time. I'm also heavily biassed towards vertical/portrait aspect shots of people!
Hope this is helpful and taken as constructive. Feel free to disagree - there's no rights and wrongs in photography after all!