Draw a horizontal line for the horizon
Sketch a large curved wave shape rising from the water
Add a thick, curling crest at the top of the wave
Extend the wave forward with a sweeping motion
Draw smaller waves and ripples around the main wave
Add foam and spray near the crest
Sketch a shoreline or coast in the distance if desired
Include buildings, trees, or objects for scale if desired
Darken the underside of the wave for depth
Refine the outline and erase extra sketch lines
Add shading and texture to the water
Finish with highlights on the wave and foam