After the first very simple drawing it should be enough to see the likeness and no more. Then next apply an undercoat of light pink darkening in shadow spots. Important to have an undercoat as it helps with shadow. Normally I would use a light blue or light purple but because of the multi coloured flesh tones I think the first here should be light flesh. All portrait work is a personal thing it is different from one person to another, this is why so many portrait artist are self taught as each has after the basic are taught have to find their own thing.