How to shop fashion sustainably?

Hi everyone. I want to ask for advice on how to shop sustainably, or more ethical and eco-friendly. What's your shopping process?

My experience in the Philippines is shop in thrift shops or look for overruns, and repair clothes I already have. Unfortunately I haven't seen any sustainable brands and have any thrift finds where they make fashion I prefer, which is usually gen z fashion that you find on pinterest. Mainly but nit limited to streetwear, academia, and y2k I think they're called. A brand I found that fits these is Carmico.

Another problem I have is I was thinking of buying something from the thrift store and just customize it to my liking to a tailor. But when I tried customization before, I wasn't really satisfied with the results. And as of now I'm not really interested in making my own clothes. Do you have any tips? Thanks!

Edit: Another brand with designs I like is Koi Footwear, though I'm unsure on their sustainability.