I really love your character design. <3 Using an airbrush to shade is honestly something that hindered my drawings for quite a while. Airbrush shading can be pulled off sometimes; for example, it usually looks quite nice when used to soften cell shading. I would recommend looking for other shading techniques. Doing so will drastically improve your drawings; See More▼ as soon as I stopped using the airbrush tool to shade, there was an extraordinarily noticeable quality shift in my work. I think your drawings would look rather nice even without shading, though finding another rendering technique will make your drawings much more dynamic. Anyhow, I made this thingy thing to show what this drawing would look like with two different shading styles(cell shading and textured shading). I personally prefer using textured shading, but you should experiment with all sorts of...
https://cdn1.imggmi.com/uploads/2019/5/31/be7d9d489522673839bbb0b77b663fe0-full.png