Learn how to draw a Mercedes Benz SLS AMG. You should be able to do it in around 4 to 5 minutes once you understand the proportions. The wheelbase is 3 wheels, and both overhangs are around 3/4 of a wheel. The body starts and ends at around 3/4 of a wheel of height, and the greenhouse is around 3/4 of a wheel tall. Take a look at how the relevant points that dictate the car's proportions (where the windshield starts, where the A pillar starts, where both meet, where the trunk starts and ends, etc) are placed relative to the wheels drawn at the beginning. It's all about joining those points correctly, with either flat, concave or convex lines.