Please can anyone critique
I would say reference is always your friend when it comes to the style, colors, etc. I know with anime shapes are generally simpler in design, from the faces, clothes, hair etc. The only time they generally put detail in is with muscle tone and the composition. I say all that to say, focus on simplifying the shapes for the hair and use reference from your favorite shows to obtain that style you want.
you want black hair to look like hair instead of just flat black shapes? The red areas should be white. You have the right idea of separating chuncks of black hair with a lighter outline but it should be white it just doesn't read well as red. Red is already a dark color. I get it red and black are cool but with a fully conceptualized character it could work but right now when you're studying anime hair, it doesn't look cool. Use white for highlights to help give it the feel of form and give you a chance to display hair texture. Oh and use big chunks of hair. Try to convey the chunks overlap to create a feeling of hair on someones head. It's easier said then done for someone just beginning their journey but until you get that part working id suggest not using small strands/chunks of hair. Study (copy) anime hair you'll see this done.