A soft (2B) graphite pencil and a blending tool are great fast sketching media. The trick is use the blender not just as a tool to smooth pencil strokes but as a drawing tool itself. Once you get graphite on the tip of the blender you can use it like a paintbrush to add value into areas of white paper. Warning: this is fun so do not overdo it- be sure not to cover all your whites with blended gray.
Click on the first image below to start a step-by-step slideshow.
Block in the basic shapes with a 2B graphite pencil. Avoid detail.
Add a frame over part of the drawing. “Breaking the frame” is a great way to suggest that the drawing extends beyond what you drew.
Add value in three steps, dark, medium and light gray.
Use the blending tool to smooth areas of tone and to “paint” in shadows on the rock face. Be sure to leave some of the whites white.
Add a little detail and strengthen some of the foreground lines.