This is a PDF file that includes three how-to-draw worksheets. Worksheets included are:
How-to-draw an eye
How-to-draw a nose
How-to-draw a mouth
Each worksheet contains a step-by-step illustration that demonstrates how to break these facial features down into simple shapes. There is also room on the worksheet to allow students to practice on the side. I used these worksheets for my third grade self portrait lesson, but they can easily be used at K-12 references.