This is the Powerpoint that goes along with the Kehinde Wiley Portrait Lesson. It walks through the first few days of the assignment. Looking at Kehinde Wiley's use of Art History References, use of celebrities and other people of color, creating a patterned background, measuring, creating a facial structure.
I would then demonstrate how to color the facial features yourself.
You will need the lesson, this PowerPoint, and printed out faces of celebrities. I would grid and laminate the faces for multiple uses.