All of my lingerie is made of either organic cotton jersey or tencel jersey--both have a small but necessary percentage of spandex to ensure a proper fit. The silk appliqués are made of real silk satin with a small percentage of lycra to help them stretch with the garment. I chose silk as our contrast fabric because in addition to looking very nice, silk is a natural and biodegradable fiber with minimal environmental impact. 
The non-spandex main component of my swimwear fabric is made of 100% post-consumer waste polyamide yarn, much of which has been sourced through recovering abandoned fishing nets from the ocean and recycling them by breaking them down and spinning the raw fibers into new fabric. In addition to helping towards creating cleaner seas, this process produces much less carbon dioxide emissions than is normal in fabric manufacturing. The factory itself is a leader in green practices, with most aspects of their operation worked out around being more ecoconscious. 
My hang tags, packing tissue, shipping labels, and mailers are all composed of recycled materials, and my dust bags are made of 100% organic cotton canvas. The factory that makes my woven labels uses Oeko-Tex Class 1 certified materials and less chemicals than average in its production methods. 
All designing, pattern-making, cutting, sewing, and packing is done in the same studio, so there exists no individual plastic bagging and transporting items between places in the production process. Much waste is avoided when everything is done in one place, and minimizing plastic use is a big deal to me.
In addition to all the choices above that I have made to try to practice sustainability, I purchase monthly carbon offsets through Green-e Climate certified non-profit Terrapass, where the funds go towards landfill methane capture, forestry planting projects, and renewable energy production.