Drawing lips is a lot of fun. You can make then different shapes and sizes. You can draw them closed and open with the teeth showing. Also it is easy to draw lips. Start with drawing a cross. Vertical line 1 inch and horizontal line 3 inches. Your lips will come out nice and tick. Connect the outside lines of the cross, so the drawing will look like a boat. Then draw and upside down arc, you can see it on the top right picture. On the lower lip do the same. And wuala, your lips are ready.
Lower you can see how the lips are shaded, practice your shading and the lips will come out perfect. Enjoy!
http://hubpages.com/hub/How-to-draw-lips