I like a plain old #2 pencil and add the shading as I see it on my portraits. The cartoons must be colorful, so I use pen and ink and watercolors. The portraits usually come out close to the real person… not always. I grew some hair before drawing the portrait above — some on top of my head and some more on my chin.
Here I am through the magical eye of my iPhone.
Here is a cartoon in color.