Overlaying an image is a great way to learn about reflections and focus mainly on your rendering skills. For this demo, I blew a picture to about 30 in long. From experience larger is better for vellum renders. Traced over on the backside with a black verithin. This is a great opportunity to practice your line quality; since they are there for you practice doing thick to thin lines.

 

 

 

On the back side I start to block in the wheels and ground shadow. Already you have to know your light source to determine the shadow. I want a hot spot on the side so the shadow goes behind and forward. Also I want warm to cool so I made a gradiant from Copic Artwerp Blue To Warm Grey.