I did this for a color rendering class over summer (Ya summer school...YUCK).
Its called a photo match, you take a magazine ad ,trace it (this is for developing color skills not drawing, hence the tracing) then do a marker wash as a base to develop the shadows. After that you add the colored pencil to show more detail and texture.
*magazine ad courtesy of Elle DecorAnd Taaa-Dahhh!!!
I think it turned out alright, for the first time. I should probably do over & over again to maintain my color rendering skills...