Photoshop - Pen tool on my own drawn car

The screen shot above is a copied image of the car i drew, using the book "Draw really cool stuff". 

The screen shot shows that i am using the program called illustrator, to create this image. I used the pen tool and drew around the car, i set the fill effect to red so when i drew around the car it filled it in red. After i had drawn around the car i then put the circle effect on and then i drew a circle and filled it in red. After  i had done the windows and all the details i hide the original car image. 

This is what my car final looks like after i had added the detail on the wheels. I really like this technique as it looks really professional.