Decide what needs to change
Choose a narrow family of surfaces first. List the properties you want to vary, such as color, roughness, or texture scale. Expose a parameter because it serves a real variation, rather than exposing every value in the graph.
Keep the parent understandable
Use the parent material to define shared behavior. Group related calculations, give parameters descriptive names, and use material instances to explore surface variations without duplicating the complete graph.
Compare in consistent lighting
Place your material variations beside one another under the same lighting. Check the surface at different distances and angles. Consistent comparisons make it easier to identify whether a problem comes from the material, its textures, or the lighting.