Draw a horizontal guideline for the eye’s center
Sketch a curved upper eyelid line (slightly thicker toward the outer corner)
Sketch a curved lower eyelid line (lighter and thinner than the upper)
Add the inner corner and outer corner using short angled strokes
Draw the iris as an oval inside the eye opening
Place the pupil centered in the iris (slightly toward the direction of the gaze if needed)
Add a highlight shape in the pupil/iris (leave it unshaded)
Shade the iris with a soft gradient radiating outward from the pupil
Darken the area around the pupil and along the outer edge of the iris
Add eyelid thickness by tracing the upper lid line slightly darker and with a subtle double line
Add upper eyelashes with short, tapered strokes following the lid curve
Add lower lashes lightly (fewer and shorter than the upper)
Shade under the upper eyelid crease and along the lower lid edge
Add a thin shadow line at the inner corner if desired
Clean up edges by erasing stray construction lines
Refine the eye shape and contrast (darker where the lids overlap the eyeball)