Paint a series of nine (9) small studies of landscape paintings from masters of the subject: Corot, Thomas Moran, Thomas Cole, Frederick Edwin Church, Albert Bierstadt, Edgar Payne, Frederick Remington, James Reynolds, Nathan Fowkes, Paul Lasaine, Robh Ruppel, Clyde Aspevig, Matt Smith, or Richard Schmid.
Try to spend less than 2 hours on each study, painting only the essential masses while ignoring minor details. The first three studies may be painted in black & white or monochrome with the rest in color. Complete three studies per week over a three-week period.
Consider the effect of color and value for communicating a sense of light, temperature, atmosphere, and mood. Value and color studies should be rendered in semi-abstract shapes with very little detail. Use color and value changes to indicate space with aerial perspective.
Here are some excellent examples by Nathan Fowkes:
Why do they work so well? They're small, direct, clear, as well as carefully observed and carefully executed. Here are some samples by Mike Hernandez, which succeed for the same reasons: