Texture connects us directly with our senses of sight and touch. Discovering the feel of hard vs. soft, smooth vs. rough, or shiny vs. dull, gives us information about the world, through our fingers and eyes. As a general perception, we are drawn to soft, smooth, and shiny, while hard, dull, and rough aren’t always as desirable.
How does imposing texture add dimension to your character? Do you want them to be appealing, or dangerous? Is their texture deceptive to their true nature, or an affirmation of who they really are? Every character has an exterior and interior landscape. Are these layers of their texture contrasting or complementary? Do your character’s textures come out in touchable form, such as clothing, or are they reflected in speech, action, and expression?
Back to Harry Potter for a peek at texture. I see Voldemort as a black charred core, surrounded by a slick metallic coating, covered in gashes with knife-sharp edges.
Be a texture seeker. Mentally sculpt your character with materials that reveal them. See what nuances you may discover.