Next I'll start to lay down some value on a new layer on top of the sketch to start covering up the lines.
Continuing to refine details and highlights- decided to put a roof on it, so i just painted it on with the hard brush. For the sharpest highlights I've used the lasso tool to create a hard edge, and with softer highlights I've just painted it on. Its important to think about what kind of highlights the car will be showing, and how the environment reflects onto each surface of the car. It makes it more believable at a quick read, and looks cooler in my opinion.