I think most artist at one point or another has tried designed their own concept cars. I remember drawing cars in my perspective drawing class. It was one of the more enjoyable aspects of learning perspective. And really, knowing perspective is the key to drawing cars. Without it, the proportions in your car sketch will not be convincing. We are so accustomed to seeing correct perspective that any major perspective errors in your car drawing will create unwanted proportions.
So the key to drawing cars is learning how to quickly draw perspective boxes. The boxes does not need to have perfect perspective–getting it close will suffice. In my video below, I will talk about laying the foundation for a car drawing. Then I will do a quick example of a concept car. My car doesn’t look very good as it is just quickly off my head. It usually takes quite a bit of sketching and brainstorming to be able to get a decent looking concept going. Anyhow, hope you enjoy the video.