When I was talking to a MAC MUA about a portfolio to bring in because my MAC counter required it to work there, she said that pictures of myself are nice but not to let them overpower pictures of other people, because of course it is far easier to apply makeup on yourself than other people. Also a good range of ethnicities and ages.
In mine I have a section with a few funky things I've done on myself for full face shots, and then I have a page full of just cropped eye makeup.