Lightly sketch the horizon line
Draw the main wave shapes with smooth curved lines
Add smaller overlapping curves behind the main wave
Shape the wave crest with a curling arc
Draw the wave trough with a lower sweeping curve
Add foam edges using short jagged lines
Repeat curved lines to show multiple waves
Vary the height and size of each wave
Refine the outlines to make the motion flow naturally
Add texture lines inside the waves
Shade the underside of the waves
Leave highlights on the tops of the waves
Darken areas where waves overlap
Erase extra sketch lines
Finalize the wave contours and details