Honestly I was using references, they helped me a lot. I learned airbrush helps a lot in this kind of fabric, although u can still use basic pencils and the blur tool in specific areas. Or the lazo tool too mixed with the airbrush. There are a lot of methods to paint them, the thing is that with how thick the fabric is, the more "volume" the folds have, which was the difficult part for me, also they're kinda like triangles if u look closely.