First I use a square brush for larger areas with low opacity, then a mix of this brush + airbrush + a textured blender for radial shading and square brush again for hard edges
hope it was useful. If you use CSP my brushes are for sale, while when I paint in Photoshop I use the Craig Mullins brush pack
![](https://d1s0ws440m13mk.cloudfront.net/original/3X/0/f/0f75e0217132464a52825f13c3a689f8e2cb1156.png)