Draw a light guideline for the center of the face
Sketch the upper and lower lip areas as soft, simple shapes
Add a shallow curve for the cupid’s bow (upper lip center)
Mark the upper lip’s two peaks and the philtrum area lightly
Draw the bottom lip as a larger, rounded shape beneath the upper lip
Define the lip corners and the overall width with light marks
Add the lip cleft/crease line on the upper lip (subtle, not too dark)
Indicate the separation between upper and lower lip with a gentle contour line
Block in the darkest edges: the lip line at corners and the crease between lips
Shade the underside of the top lip to show it sits above the mouth opening
Shade the lower lip to show its thickness and curvature
Use a mid-tone base on both lips before adding shadows
Add highlight shapes on the lips where light would reflect
Blend shading smoothly, keeping edges sharper at the darkest contours
Refine the form by darkening key shadow areas and softening transitions
Clean up the outline by erasing unnecessary construction lines
Add subtle texture sparingly (small, gentle lines) only if needed
Re-check symmetry and proportions against your face guidelines
Adjust contrast: keep the darkest values in the crease and corners, highlights on the upper/lower lip curve