You have a lovely style! I like your proportions and feel like you have a pretty good grasp on chibi anatomy. Although a lot of artistic choices are about style, hopefully these tips can help you still!
The main advice I think might be useful for you is to add extra details in your shading/highlighting. I feel like the stark white can be a little too strong on it's own, so maybe experiment with adding other softer highlights underneath the white. Another technique is to not use only straight, but instead create a sort of curved M- or W-shape and add that in with the lines (or use it instead of the lines) as a way to show off the shape of the hair (here's a good example of both softer highlights and shapes besides lines). The same goes for your shading - remember that you're shading hair and not spheres, so the shade edges won't be completely smooth but instead a little jagged (example here to show off hints of hair strands within the shading/highlighting).
In general, don't be afraid to use different highlight colors besides white and experiment with different shapes and tones to create more depth and softness to your pieces ^^