Sunset setting? Really?
Cicopo is right, car shots are difficult. It's all about the lighting, which is an advanced subject anyway, and even more difficult on dark colored cars - which are pretty much mirrors if you have a nice wax job. For black/dark colored cars you don't light the car itself, you light the areas around the car. This creates bright reflections called spectral highlights, and they are what define the curves of a 3D car in a 2D photo. White/light cars are exactly the opposite. Again, you don't light the car itself, but you use unlit "reflectors" to create dark lines on the car, so you can again see the contours. Colored cars inbetween light and dark can use either/both techniques.
The really nice shots you see on magazines are usually done in a studio where they can control this lighting. Even the outdoor shots usually involve giant reflectors to gain this effect. Bar this level of lighting you need to use what's available - sunlight (overcast days), far away lights, walls/buildings, etc. The classic sunset photo is great, but if you don't get light on the front of the car you'll just have a silhouette and a pretty sunset; or a car and a white background.
And finally, most the good shots have heavy "photoshop", or "post production" as it's called.. A technique called "Dodge and Burn" is going to help create those bold shadows and highlights. Much like a swimsuit model, you just add the sexiness in post. Personally I would also try a technique called "Frequency Seperation" to get the shadow transistion I want, but I never have tried this technique on cars; it might be quicker to just use heavy D&B. There's going to be plenty of color manipulation, and a good old dose of the high pass filter to pull out all those lines.
