>>18505864
i would start by hoarding scans of mid century catalogues and learning about the brands that way then find the actual garments themselves on ebay etsy vintage stores etc and study the pics closely and learn about the garments themselves. study the fine details and if you don't already know, start learning how to tell exceptional garments apart from high quality from mid quality from low quality. sold listings are a good place to look -- a lot of the high quality stuff already sold and we don't care about buying anything yet at this stage.
and fyi not all the catalogue brands are good. jc penney especially does this shit a lot where they make 7 jackets that look identical in different product lines and they range in quality from the real mccoy to budget lines making the same jacket with polyester blend. yes if you didn't know this polyester has been ubiquitous as shit since around 1950.
there's brands outside of the catalogue brands, but those are a good starting point. the algos will just feed you the other shit eventually i'm sure. if you see a garment you like and think is cool learn about the brand.
p much how you do it.
the payoff is imo vintage jeans always fit a little better than repro.