The pages people buy to get better. A realistic face has nowhere to hide: skin tone, the turn of a cheek, the shadow under a lower lip. Get it slightly wrong and everyone can tell.
That is exactly why they are drawn pre-shaded. The hardest part — deciding where light falls across a face — is already done, so you spend your time on color rather than on structure.
Women, children, elegance and flowers: Lucrecia, Maisie, Bonny, a girl in a hat. If you want one page to practice skin on, take one of these.