Andy, word of advice - ignore any post on this forum related to lenses, cameras, flash equip, and especially at all costs avoid anything having to do with Pocket Wizards!
You can buy equipment until you are blue in the face and red in the bank but my opinion is you should outgrow the equipment you have before you buy new gear (you wana be a photographer or a gear collector?)
**quick note to all the POTN members, I love you all. I'm as much of a gear junkie as any of you...but let's not corrupt this young photog eh?**
You're shots are nice Andy. And it's great to have willing models! When you get someone who is natural in front of the camera and willing to sit while you experiment you should give them all the free photos they want! Hold on to them - they are invaluable.
You said you are shooting these for a class right? Have you talked about the Rule of Thirds? Do a google search, or search the forum if you haven't heard of it.
The basic idea is that you divide your view-finder into a three by three grid (so you get 9 boxes). You then place points of interest at the intersections of the lines.
Now, here's the thing with art rules. They pretty much exist to be broken right? And true that may be, but most of the best artists are all capable of producing really boring rule following works of art. Get good at rule following, then you'll get good at GOOD rule breaking. (at least that's one theory)
The other thing that I'm sure you have talked about in class, or will soon, is to be careful not to cut off parts of the photo that our brain really really really wants to fill in. i.e. if there were a form or shape that we all know well...say a leg for example...and you cut if off right at the joint...like at the knee perhaps...something happens in our brain and we really really really want to see that leg continue. It becomes a huge distraction.
Take your first shot for example. There are a lot of lines that a viewer wants to see the end of. Her elbows, her legs, ...the whole bottom half of her body for example. Same thing on your second shot - cut off at the knees. When framing a shot, try to break bones, not joints (in other words cut off in-between joints.) For some reason we can be at peace with a leg that ends mid thigh, or an arm that ends just below the shoulder.
I think the shots leaning up against that wall have the most potential. You get some really cool lines from the siding that lead your eye straight to your model which is always good.
On the closer up one (IMG_6197) we lost the very bottom of her right shirt sleeve...my eye just goes down there and I desperately want to see that little bit that is cut off. It's that whole closure thing. Keep the lines closed. If you were to crop this one tighter and make the bottom of the frame just a bit below her shoulder I think it might be more pleasing.
There are some things you could have done with a reflector too. I'm talking a white piece of matte board or something (Arts and crafts stores have them on sale all the time. Hobby Lobby just had a %50 off sale and I bought a bunch of new ones. They cost $3 when they are 50% off.) You could bounce a little light on the dark side of her face for fill to bring up the shadows and make the stark contrast between the light side and dark side of her face a little less stark.
All of that said, here's what I'd suggest. There are a million things to think about when taking photos. what you have to do is train yourself to make them second nature. So pick one thing. Just one. Like the rule of 1/3 for example. And FIXATE on that. I mean become obsessed with it.
Forget lighting, forget backgrounds, forget everything...just frame up photos in the classic rule of 1/3. Then stick all of those photos in a folder on your computer and label it RULE OF 1/3.
Then, start experimenting with some reflected fill light, but don't forget the rule of 1/3. Keep building the skills one at a time, and always review your photos on the computer and make mental notes ("oh, the fill light is good on this one...but I forgot the 1/3 rule" etc.)
If you can be that methodical, you can really improve fast!