I wonder if doing what Sir Quentin Blake does when he does his illustrations would help?
I watched a youtube of him explaining his process for making kids picture books - his images are always fresh and dynamic.
He draws what he wants, dozens of times, on ordinary paper, then when he's happy with the composition and look, he puts it on a lightbox with a heavy piece of watercolour paper over it - so he can hardly see the sketch underneath, and draws it again (in ink!), just using the under sketch as a guideline.
I guess the combination of having drawn it a dozen odd times already, with not being able to see the under image well enough to trace it fussily gives the image that freshness and life.
I utterly love what you've done here ..that hair, wow.