Working with a Limited Color Palette at the 2014 Urban Sketchers Brazil Workshop ( http://citizensketcher.wordpress.com/2014/09/19/limited-color/ )
Contour lessons An excellent example of a concept which is taught and (in theory) learned by all art students. It's harder then it looks but will diffidently help not just with drawing but painting too. I always say that what makes art so hard isn't what you can draw, it's about whether or not you can convince the viewer that it is real and has mass.
Art Deco Fashion Drawings by Helen Dryden American Artist