For brushes: I actually just use the default photoshop brushes! But here’s a “tutorial” showing my methods as of late. I don’t have the sketch anymore so it starts at the inking stage, apologies.
(The trick I’ve found for clean lineart is to make your canvas 400% larger than the ‘final’ size [i.e if you want the finished image to be 1000px wide, make your canvas 4000px wide] - and ink everything with the magnification zoomed in 200%. For printed images, make sure your image is 300dpi.)
2. Add flats.
3. Shade using a broad airbrush and a ‘multiply’ layer. I shade cool colors using blue, and warm colors with red or brown. I put this layer on a low opacity- 30-40% or so.
(Look around the ears in case you can’t tell where it’s been shading- I’ve been a bit more minimal with my shading as of late.)
4. Shade using a smaller airbrush on a second ‘multiply’ layer for areas of finer detail. I also put this on a low opacity- but usually make it a bit darker than the other shading layer.
5. Use a white airbrush on an ‘overlay’ layer for highlights. Again, I use a layer opacity of around 30-40% for this.
6. Add a texture using another ‘overlay’ later.
And you are done. I hope that helps! Thank you so much for your interest in my work!