When I finish a costume, I often discover I’m not actually done with it. There are always improvements or changes I want to make, and I know I’m not alone in reevaulating my work. Cosplayer Nebulaluben made an excellent looking Tali’Zorah costume, but she decided she wanted to work on the mono suit to change a couple of details and make them better. She dissected the existing suit and cut the pieces apart on the seams. She replaced the middle areas with shiny black vinyl fabric that she painted hexagons on with spray paint (she printed a template).
After adding that detail, she worked on the tops of the sleeves to make them more accurate to what the character wears in Mass Effect. They were smooth, but they should be striated. She took a piece of shiny vinyl and scored it with many parallel lines, and she ended up with a neat, textured look that she attached to the rest of the sleeve.
She details the process at her site, and she has several photos showing the adjustments she made to the bodysuit.