I took a photograph of a raven when we were at the Grand Canyon in April 2008 (see image below). I didn't really like the photograph too much, but it was a nice template for trying to create a vector illustration along the lines of what is shown here:

http://www.ndesign-studio.com/tutorials/tracing-photo

I drew outlines of areas with approximately the same color, reducing the number of unique colors to eight. I don't think I would have been able to get anywhere without my Wacom graphics tablet, which makes tracing the outlines fairly easy.