If you want to draw a mouth that doesn't look flat, you need to understand and show the structure of the mouth. The structure of the mouth can generally be divided into upper and lower lips, lip bead, corners of the mouth and people.
1, ordinary lips.
Step 1: determine the range and position of the mouth, pay attention to the position of the mouth corner, and align with the pupil.
Step 2: Draw lip bead and the lip seam, and draw it in the middle of the mouth.
Step 3: Finally draw the upper and lower lips.
2 minimalist lips.
Step 1: Draw two arcs and pay attention to the consistency of the lines.
Step 2: Emphasize the shadow of the corners of the mouth.