Draw a rectangle of a medium size at first. You need this figure to know approximately how wide will be the lips and prevent them from going beyond the borders.
We need a horizontal line to mark the size of the lips and in order to divide them into upper and lower ones. Pay attention that the line divides the rectangle not in the center but slightly above.
Draw the lip from the horizontal line’s corners to make it smooth. It ends at a small distance from the rectangle’s side.
We don’t need the dividing line. You can erase it.
Upper lip's line
Draw a horizontal line that slightly curves down from the corners of the lower lip.
The upper lip is uneven, there is a dimple in the center. Correct the line in a proper way.
Look at your drawing and erase the unnecessary details.
Draw another line at the top, making the upper lip. It must curve in the center.
The lips have already been drawn. You can erase the basis. Erase carefully near the corners not to damage your drawing.
Draw a curved line under the upper lip, marking the teeth area. You need this line to make the teeth even. Start drawing them in a form of the rectangles with the rounded corners.
Erase the line and correct the teeth form when they will be drawn. Draw the small teeth at the edges because you can’t see them completely.
Collage of the stages of a smile drawing