The Grand Canyon's layered cliffs, deep shadows, and vast scale make it a compelling but challenging subject. Here's a practical approach:
Lightly sketch the canyon's overall silhouette—rim line, major buttes, side canyons, river line. Use simple geometric shapes (wedges, blocks, cones). Keep lines loose; accuracy comes later.
The Canyon is a layer cake of rock. Draw horizontal strata lines following the topography. Key layers (top to bottom): Kaibab Limestone, Toroweap, Coconino Sandstone, Hermit Shale, Supai Group, Redwall Limestone, Muav Limestone, Bright Angel Shale, Tapeats Sandstone, Vishnu Basement Rocks. Each has distinct texture/color.
Determine light direction (usually morning/evening for drama). Shade cliff faces: vertical planes = dark; angled ledges = mid-tone; horizontal caps = light. Use cross-hatching or continuous tone for rock texture. Deep side canyons = near-black.
Layer warm reds, oranges, ochres, purples, grays. Burnt sienna, raw umber, yellow oxide, cadmium red, dioxazine purple. Build transparency; let paper show for highlights.