Before to draw any sketches, search after some blueprints of car, ideally in vector paths, along of course with many pictures done by you to your or client car. Analise the lines, shapes and placement of accessories (car handle etc) and try to match the best space shape and start the reactor.

STEP 1.

For exercise, you can download this Renault Kangoo vector blueprint.

STEP 2.

Make an outline shape of car to can create compound shapes, subtract from it etc. Depending of how the  vectors  are done, you will need to use pathfinder tool, direct selection tool and make some anchors to join.

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STEP 3.

Make your design and crop it into the shape of car.

STEP 4.

Save your work

STEP 5.

Create a new document and create a color car using the vector blueprint. For color palette and gradients use the car pictures.