1. I like it, especially the conception. I like the angle of the chair and subject. I think a little more space below the feet and less above the head would help with compositional balance, as well as straightening the vertical elements in the composition, like the wall, bricks, etc. Our eyes tend to go first to the brightest element, which in this case is the large white panel, so I'd tone that down or eliminate it with a different POV when shooting, and even do some selective vignetting to focus attention on the model more. I immediately thought this would be pretty neat if it were 'grunged up' a bit too, kind of like this as an example:
2. The subject seems to take about a quarter of the composition, in the lower left quadrant, which I'm not really on board with. Also, I'm not able to connect with the subject without the eye contact, especially at that distance and with all the space surrounding him. The space above and to the right just seems like too much and isn't all that interesting to me. The hazy white look to it, as mentioned by others, isn't working either for me. Perhaps a lens hood is needed while shooting, though you can probably bump the contrast in post to help with it.
3. With the others, I think this is just too far away to be of real interest. It's a nice tree and all, but we're getting so much more, like the uninteresting white sky, the uninteresting foreground grass, and the foliage on both sides that don't really help. The whole thing is centered, and that's not really working very well to draw interest either I don't think. It looks like the subject and tree trunk and branches might be really interesting, considering the elements of light that appear to be present there, and I'd be more interested in seeing that detail much closer. If you can retain the detail after a crop, it might be worth trying.
4. The centered subject isn't working for me here, mostly because he's not engaging with the viewer with eye contact, but is looking out of frame. That said, I think this would work much better if he were positioned more to the right in the composition, giving him more area in the composition to "look into". The branch frame is nice, but a bit too close to his head for my taste, and the lone thin green stick coming in from top left corner is drawing a bit too much interest I think. As mentioned by others, the focus needs some work. I'd also suggest a bit of fill light to deal with the harsh shadows, especially under the chin. Working in bright light like that, a simple white reflector using almost anything from a poster board to a sheet stretched over a frame will do wonders for you, so you might give that a try.
5. I like this and would rate it the #2 shot of the series. I'd say get in closer and exclude the extraneous foliage, especially all the space above his head. Remember, there's nothing wrong with cropping to a square format either - some of the best portraiture ever has been made in that format. This is another one that I think would look really good 'grunged up' some.
It's good work for your first attempt. Keep at it.
