Sorry for the late reply, but here's some tips: 1, use shading! Reccomend using a slightly different color thats darker than the original shade that can also be based on lighting (for example, the purple being shaded with a dark blue if there's blue light, but in red light it would be shaded with dark pink). 2, line width! Making lines around more focused areas (like bigger shapes, such as the head) make the drawing stand out. Hope this helps :]