I recently read the book Wear No Evil by Greta Eagan.
This is a great starter book for someone looking to be more eco-conscious with their clothing choices.
In short, Eagan lists out an "integrity index" of sixteen factors to be wary of when purchasing clothing. She says to focus on 3-5 aspects in order to be realistic, style being the first factor to consider.
For me, I personally like reduced water usage, biodegradable, local, and secondhand. If there are causes I would like to support, the first one that would come to mind is Charity: Water, or any other organization dedicated to clean water, and reducing water usage. It turns out a single, cotton t-shirt can use massive amounts of water to create and dye. I will now look for vegan leather that is a byproduct of the meat industry or at least is secondhand. For one, it's biodegradable, and two, pleather contains myraid chemicals. I would much rather see a trashed leather jacket naturally wearing out, than a pleather one living indefinitely in a dumpster. In general, I mostly shop at thrift stores, and try to support Made in the USA items. Even more locally, I would also like to support Chicago artists and companies. And I love thrifting. It's the thrill of the hunt. I've found some great things while thrifting. It's just an added bonus that I'm giving these items a second lifecycle.
In short, it's not that hard to be SOMEWHAT eco-conscientious after reading this book:
You're eschewing fashion for the sake of fashion, but that doesn't mean you sacrifice it.
For more check out: noevil.com
And buy the book!