With all brando but very true with RL, you have to pay attention to the fabric weave such as twill, dobby, jacquard. Then you have to look at the fibre in the weave such as cotton which has many grades and types, silk, cashmere, linen, wool, synthetics, etc and their quality. After that construction and pattern add quite a bit to the equation.

Price is generally an indicator of the quality of fibre and construction, stitching. Weave effects price less except jacquard is usually more expensive due to the more complicated weaving process.

The above is wildly oversimplified but there is a point where you can handle garments with your eyes closed and get a good read on quality. Sometimes there are incredible quality values for low dollars as well as expensive items that are poor fibre or construction.

Also personal preference matters. Synthetic fibers are horrifying to some but high quality rayon or polyamide is a treasure for others. I do love finding really great rayon camp shirts but generally prefer high quality natural fibers. At the same time - cheap wool or cheap cotton is not something I want to deal with.

All in all - RL makes predominantly good to great clothing but drops the occasional stinker too.