I doubt if anyone can improve these, but I have some suggestions for trying it again.
Time of day/lighting issues: Find a way to get better light. Either very early or near the end of the day will give you better light. Use your best artistic eye to consider where the light is coming from, and position the car accordingly.
Background: Find a better place without distracting elements in the area.
Lens: You shot this with a wide-angle lens. This has emphasized the near front corner of the car in a way that is not pleasing to the eye. The huge-looking fender and bumper (all the same color, too) just takes over the shot and detracts from the model. The idea of the model is to enhance the car, but this huge red front is not working. Use a longer lens (or zoom to telephoto) and back up accordingly.
Pose: The right front corner of the car (as mentioned above) is perhaps not the best feature of this car. Try different angles by re-positioning the car to show other parts of the car. Try some shots with a slightly higher camera position, and then try some shots of close-up details. Mix it up a little and there will be a few shots that work.
Model: First pose (standing) is fine, but asking her to sit on the ground is not working. If the model is in the shot, make her a more prominent component of your composition. IOW: don't frame so wide. That extra space behind the car is doing nothing for your composition, and being so wide makes the model take up much less area of the photograph. Also, she should smile.