A few years ago, I asked several Artists and teachers about an effective way to self-study. They all suggested doing tonal composition studies from old masters. Tonal Composition study is basically an exercise that develops observation skills. It teaches you how to observe, simplify and distil a complex image into big, simple shapes and 2-3 values.
Simplify, group and then simplfy some more is the lesson here. Below is an example of tonal composition studies I did from November 2011 to January 2012. These were drawn in my toned paper sketchbook, about 1-2 inches in size. See image below for complete materials list.
My daily tonal composition studies from November 2011 to January 2012.
My sketchbook and materials I typically sketch with. These are perfect for doing tonal studies and quick tonal renderings.