Concept: I wanted to play on the name LEAF, but I didn't want it to be too cliched. This car can be likened to a leaf in that it creates no air pollution, little noise pollution, and doesn't rely on petroleum to run.
Images: I wanted the car to blend in with nature, but stick out as being unique, interesting, and perhaps thought-provoking. I found a really nice, simple background with the tree and grass in silhouette. The leaves of the original tree sort of form a car's silhouette too, so that's what prompted the final imagery.
Font: Simple, clean, modern, with little overall footprint. Just like the leaf. Also, I wrote/arranged the sentences in a way that subtly hints that the shape of a tree itself.
Tools: The car itself, I used the Quick Selection tool to get as close to the overall car shape. After refining the edges, I creating a work path out of it. I then used the Pen and Direct Select tools to zoom in and refine the path further. The car originally faced in the opposite direction, so I flipped it, but I had to keep the words "Zero Emissions" printed on the side of it readable. I used the Clone tool to make the colors of the word patch and the flipped car blend with each other. I used adjustment layers to color the car and sky a leaf green. Then I used Multiply and Soft Light layers with the leaf detail to create the leaf texture on the car.
Challenges: I went through a TON of ideas. I'd start on the imagery, and then at some point throughout my work, I'd take a step back and think that it wasn't right.