Anime faces.

Thanks!

One approach you might try is finding some photos/drawings of an anime/manga style face you like (ideally front, side, and 45 degree angled views) printing them out at the exact scale you want your head to be, and then taking measurements (spacing between eyes, nose, mouth, etc.) directly from those images and matching those while you model. That's a technique I learned from an interview with a guy who does lifelike portraits of characters for Sideshow's 12" figures (of course, in his case, he was using photos of actors/actresses, but the same principles apply).