That's not a sprite, it's a 3D render
Also, I think you're going about this the wrong way. Your 'dither' lines in the hair just make it look messy and not at all like hair.
Of course, the best way to make hair is study real hair, identify what makes it look like hair, and draw that. But since it seems you are none too interested in doing things the slow way, I'll tell ya' something else.
I dug up some stuff from FFT, it's pretty good examples of how you can make hair look good and stringy with pixel art.
(sorry for the huge images, too lazy to separate. from the sprite sheets.)
Miss calculator uses simple segmentation. The slight wavyness and soft transitions from segment to segment work to make it look more like hair.
Now, the Squire there, well, he's got a slightly more interesting methodology
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Square Soft put highlights around the dark parts where the hair splits into different groups. What this does, far as I can tell, is make it look more "stringy" without actually trying to draw individual hairs.