if you mean the texturing of the fabric, here's a lil demonstration!

start with a repeating bg texture-- this can be a brush, or just a flat image texture/pattern-- in whatever colour you like. I like to go with gold usually!
using a soft airbrush eraser, gently erase parts of the fabric where it would be 'further' from the viewer. places like breasts, tummy, shoulders, etc stick out more, so they'd have the most colour still. this is just to get a little bit of depth!
you can end there, but there's also two more steps you can take: the first is in the video, where (using the same colour usually) using an add (glow) layer, you can softly airbrush in some lighting-- this works best with, again, gold! it looks like shiny metal woven into the fabric
the second I didn't show, but you can use the liquify tool (or mesh transformation if your program doesn't have liquify) to adjust the repeating texture to flow with the body a bit more, pushing and pulling it with the weight of the fabric
I hope that makes sense! <3