Multiple comments...
1. For new models, if there is clothing they like, feel good in, then they pose better. Their poses are more comfortable and more assertive and confident (they aren't thinking "does this dress make my butt look big?"). So I get the shirt. That said, I'd shoot her in the shirt and then change. Or put a shawl over it or over-blouse b/c it is distracting.
2. Let me start with picture #5. Common mistake--she looks like she's saying "I surrender." I'm a big fan of asymmetrical poses. Try the same thing but put one hand behind the head and another on the neck. Or change the angle of the elbows.
3. She looks like she's short OR has big and short biceps. So any pose where she bends then (like in #4) emphasizes the size of the bicep and makes it look even bigger (as opposed to #3 where it's more proportional). You can find a pose you really like but then you need to adapt it to each body type b/c we're all individuals. Also for #4, I'd crop it so it's portrait/vertical. Keep that diagonal line of the tree trunk (that's a good thing) but don't have the tree trunk take up half the picture and pull our eyes to it. #3: good pose, would benefit from a narrower DoF so we had more bokeh, less focus on the background. Her face seems a bit blowout. I also wish the hands weren't at the same level....maybe one goes into a pocket and the other on a hip or the rear pocket or behind her neck. #2 has potential but there are a lot of small flaws to work on with this pose....distortion (man she's got some giant hands...oh wait, that's lens distortion...so use a zoom and get further back from her)...shirt is wrinkled which is both distracting and makes her look fat (use tape or a clamp to tighten it up in the back, if you have her twist to one side that takes off 5 pounds). Light on her face is very harsh. I'd put her in shade and then use a reflector to bounce some soft light in to that face. I'd also lose the necklace which I'm sure she loves but is distracting in this case. Last shot (#1)--full-on frontal shots are rarely complimentary to people, they tend to add pounds (so she looks chunky in this photo). Nice angle to her face, nice light, good background color. I'd have her extend her right arm (so it was straighter) which will make that right bicep smaller. I'd have her orient her hips a bit more to the left (so her upper body is effectively twisting to the right) which will take off 5 pounds. And I'd remove some wrinkles on the front of the shirt (either tape/clamp in the back or some post-production work).
Some nice potential here (with the model and location and your ideas). Show us shoot #2 when you get a chance to work with her again. Good start.