Decide the light source direction
Draw the main object first
Identify the side opposite the light
Sketch the shadow shape on the surface
Keep the shadow attached to the object
Make the shadow darker near the object
Fade the shadow outward
Match the shadow angle to the light direction
Adjust the shadow length based on light height
Use soft edges for distant shadows
Use harder edges for shadows close to the object
Add cast shadows under overlapping parts
Blend the shadow smoothly
Compare values and refine the contrast