Hi there ThatOneGuy,
The photos are good for a beginner. Here are some feedback from me :
General Comments :
When taking portraits - try to see when the light sources are coming from, then try to pose your subject because usually common people does not know what looks best in front of the camera. Rule of thirds might be good here as well for your images. I have written a few photo tips on my blog, please do feel free to check them out (www.lightingjourney.blogspot.com
I am assuming you are shooting an environmental portrait type of look, which is pretty cool. My suggestion is that you might want to get the subject to have her right arm to be angled away (not aligned to her body) such that you could see a separation between her body and the arm (creates depth and more pleasing look). Rule of third might be a good idea as well (placing the subject a little bit to the left or framing it more to the right).
For this the car behind her is somewhat huge and it gives the weight to the car rather than the portrait so what you can do is to bring her closer to the camera which will give the focus and attention more to the subject instead of the car. When you are shooting cars, maybe it is advisable that you should not cover the front of the car so maybe place your subject to the right of camera.
Hope my feedback helps. Keep on shooting.