[Trojan Piglet]

So, I've been getting more and more into the vectoring and from scratch creation of cartoon/realisticish art. 
For example, The work of Motusora. 
So my question is, does anyone have any references to better understand shading and techniques in Illustrator/photoshop for achieving the "Realistic " texture that makes his and many other illustrations really Pop. 

 (Any corrections in my terminology and naming of these style would also be appreciated)


 Thank you for any help  🤝 Happy Halloween!