Long hair like this is always going to present a problem but it can be done by following a few rules. Apply the light tones first then gradually introduce the medium tones interweaving them between the light hairs. Don’t attempt to add any of the strong dark colours at this stage. The light and medium colours can be erased if need be and redrawn if desired. Once you are happy that you have a good representation of the hair then gradually add the stronger darker colours.
Another tip I can give you is try to keep the highlight in the eye as small as you can, in this picture they are a shade too large.
Overall you have done a great job of two difficult subjects, well done.
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