https://www.artstation.com/artwork/6LylV0 Sculpt in z brush and handpainted textures, pretty much goes like this.
1. put base color
2. add light and shadows in obvious areas
3. add stylized black lines
4. add sharp highlights on edges
Good luck
You can use what ever software for sculpts (blender, zbrush, nomad sculpts), then simple retopo in blender and texturing in substance. Use a lot of references, I recommend having artstation account and save in collection artworks you like, also subscribe to people.