This is a good attempt. You have a good general idea of how hair is shaded, but there's some things that could use some adjusting.
First, around the head and neck(as in the underside of the hair), the hair will be a lot darker. Frequently people will outline in the second darkest palette color for the underside of the hair. Your strands on the underside are very good, but you should avoid using so much of the hightlights there because this is a dark section.
As for the top of the hair, the way shading will work is it darker around the ears and part, then you work your way to lighter hair. The strands on the top are very chunky, try thinning them out.
One final picky thing, the outline of your hair needs to be cleaned up. Outlines should be 1-pixel wide and smoothly done. Especially on the piece across the face, your outline is very chunky. Hayley actually described it very well here: Heva's Hand drawns!