Top is the sketch during class and the bottom is the sketch after class. I gave myself a 3x6 in space to work in for proportion practice. 

I'm a painter so I ended up shading more for color value, its a black car, the second time around. 

I think a tip to drawing from reference or life is to use the wheels as a measurement. Kai mentioned 2-3 wheels between front and back, so I ended up using that for other key points on the car. 

I liked not being able to erase, I think that helped my brain not focus on details right away.

Reference used was from vscda.org btw.