Hi there. Sorry it took so long to reply.
This is a good start to a story I love how poetic you are.
The only thing I suggest is maybe trying different methods of shading (like hatching or circulism) Here's a good resource to help you:
https://rapidfireart.com/2017/08/30/lesson-8-introduction-to-shading-techniques/
Another thing that you can try is working on facial expressions. Facial expressions are complex, but they will give the character more depth.
Lastly, color can also help with mood of story. I noticed that you're already doing this which is good. For example, blue is often associated with sadness whilst red is associated with anger. Subtle color changes are key to showing mood. Also, the more intense a color is, the more intense of a mood.
Here's an interesting video on the subject that I found, and it will change your life:
(warning: flashing colors)
I hope this helps.