Welcome to ME, to start with.
There are several things you can do to take great pictures of your car. Good lighting, composition (what's in the picture), and focus come to mind.
Start off by taking pics when the sun is out, but keep the sun over your shoulder so the car's details are well lit. Later on, you can experiment with glare, lens flare and other things that can make an image pop.
For composition, keep in mind that your car is a horizontal shape - it's wider than it is tall - from most shooting angles anyway. Step back far enough so you can take a landscape shot (wider, not taller or square). Then think about what's in the picture. Make sure the car is the most eye-catching thing in view. If people are distracted by something else in the pic (like a bikini model or a more colorful car), they won't focus on your car. Again, you can play around with alternatives as you get better at taking pictures.
Focus is critical. Looking at your example, the very front of the car is the most (though not completely) in focus. But the most prominent thing in the picture - the thing that draws the eye - is the hood with it's big black stripe, and it's kinda blurry. Plus, the direction of the stripe draws the eye toward the windshield - which is even more blurry. Using your iPhone, tap on the screen where you want it to focus the most. Play around with that. Draw the eye to the parts of your car you want people to concentrate on by making it the most in focus. Shooting in sunlight will also help by giving the camera more light to work with, potentially expanding the amount of area that's in focus.
Hope that helps.
2003 Sonic Blue GT Vert