Hey! Nice work here! You already have a solid foundation to build on! The main thing I would do is create a stronger contrast by pushing the shadows further. Even a simple shadow pass (without adding bounced light, ambient occlusion, and other rendering effects) would help the illustration feel much less flat. To make the face stand out more, you could also darken the pants. Even if the original reference doesn't do this, remember that as the artist, you have the freedom to guide the viewer's eye wherever you want. A quick note about colour choices: I understand that being somewhat colorblind can make selecting colours a bit more challenging. Because of that, it might be helpful to occasionally use the color picker, not to copy colors directly, but to verify that the colors you've chosen are reasonably close to the reference. You could add more orange and reddish tones to the face, especially around the nose and cheeks, to bring a bit more life to the skin. As for the hair, blonde hair isn't purely yellow. It's usually a combination of yellows, oranges, and even browns in the shadow areas. You'll gradually learn these nuances over time. :) One thing I can recommend is practicing with simple painting exercises, such as rendering basic forms while focusing only on values and lighting. If you have the opportunity, I'd highly recommend taking the Intro to Painting Roadmap at Artwod! Hope this helps!
