I feel like the biggest thing that helped me was learning about clothing construction and materials. A lot of stores tend to have hidden gems that can be constructed very well and made with quality materials. Things I tend to look for are a good lining in dresses and jackets, natural materials or blends at least, taking a good look at the stitching work and how sturdy the seams feel (give it a delicate pull if in person and see how the threads in the seams hold up), how thick a material is, etc. I've found a lot of really nice stretch silk blend shirts at thrift store in great condition that have become staples.

Another thing I've discovered on a budget is that good quality syntehtic products exist. I usually only buy skirts in synthetic materials as skirts in general are rather breathable. Thick sytehtics with a good weave can last a long time and have the perk of being wrinkle free if you're getting the right stuff. I also like synthetic outwear as its not right next to my skin making me sweat but still keeping the heat in in a good way if that makes sense.

If you're on a budget like I am in my twenties, educating myself to hunt down quality has helped a ton. I've started to invest more in some pieces one by one by quality brands as things have worn out (shoes primarily) but until then, I will just hunt down those quality outlier pieces in person as much as possible and thrift what i can.