For large objects like a car, you need to make a circle! Use a piece of rope and a peg hammered into the ground. walk out the required distance and then using either paint, sand, flour walk around in a circle dropping or painting the ground.
Once this is done and you have a perfect circle, stand on the circle and take your photos! (Make sure you put the car inside the circle ) Make it even better by making it into a "pie chart" this way you also get the "even" positioning points where you need to stand for each photo/image to be taken.
Hope this helps, Smooth