Hey there! It looks so cool! Love the style of you character :D So, I'm going to focus a bit on the colours. I'd say that painting using more saturated colours to avoid "moody" ones. The face, for example, since you painted it with a desaturated green, it looks "lifeless." I increased the saturation there. On the other hand, when shading, do not use the same colour tone but a darker one instead; shade using a colour that goes in the opposite direction. If the green is closer to the yellow tones, then shade using a cyan or blue tone. I applied this same concept to the hair. The bright colour is closer to the orange tones, so the dark colours should be closer to the purples. This way you create more dynamism in your painting and avoid making it look "flat" (not flat of volume but of colours). You can also increase the light from the purple-ish energy and paint some bounce light on the face. Hope this helps!
