I got this project done by, first, taking a picture that my face, not including the background, was symmetrical. Then, I made an outline of the left hand side of my face. Our class decided that we would do the left hand side of our face and then what we had would be symmetrical. Later, We started an outline of our hair, then mouth, then eyes and eyebrows, and then colored in our entire face. The way we did it was by using the line tool to make triangles/polygons in our face.
The easy way of Low Poly and hard way are different but not that much different. If you get a big spot in average it will give the average color, but with the other way you can be more specific with your color. I like the average way because then it's the computer's comparison instead of your own. Plus, a lot of the work is for you to do doing Poly Portraits the hard way. Also, it looks a lot better.