Hey! I love your illustration style! I’d love to be able to do something this stylized haha. That said, what I’m seeing here is that your main light source is in the background, but at the same time, you’re painting the character as if there’s a warm light hitting her from the front, which makes the lighting feel inconsistent. If the light is coming from behind, then everything facing away from it should be in shadow and darker to create a stronger contrast. So the first step would be to darken the character and remove those cast shadows in the backpack. You could even add a subtle glow around the silhouette to make it stand out more. Also, try playing with warm vs cool colors. If your light source is warm, then everything it hits should lean warm, while your shadows shift cooler. This creates a much more interesting color contrast. Hope this helps! :)
