I think your darker shadows are not the main issue but the lack of lighter values, adding highlights and light on the them both makes them more readable. For texture, you can simplify the concept to one aspect of it, by thinking of everything in a reflective to matte range. The more reflective something is, the sharper the highlights and shadows are; the more matte something is, the softer the transition from light to shadow is. Also study material rendering. If it helps you can look more into league of legends splasharts as references and observe how they render different materials like hair, cloth, leather, metal, etc. | Artwod Feedback