I don't know much about the mechanical level to it, but I know for a fact he draws heavy inspiration from Greek statues and fashion magazines.
It's why the faces in his post Stone Ocean art all look like fashion models and why the costumes have been that way since the beginning.
If you look at characters in the background of any part, it's blatant how much research Araki actually puts into the locations he sets his stories in, not just the info dumps but there's a lot of subtle nods to the culture of wherever he's referencing like the things people eat and the jobs people work.
Also there's a heavy emphasis on thinking looking nice, but not necessarily being accurate, despite his skill level and clearly demonstrated capability such as the OP image.
By all accounts, a lot of the poses he draws are technically "wrong", look at Josuke's arm here and Bruno's feet, but it's rarely noticeable because of how much work and skill goes into everything surrounding them, if anything the term I'd use is "idealized".
Said poses are so well known partly because they are flat out impossible, but still remain aesthetically pleasing and unique enough to still be positively memorable.
Part of this is his strong sense of 3D space and color, everything seems to exist coherently to these exaggerated features, and despite being black and white you get a strong feeling for whatever palette he would actually use if this wasn't black and white. It's why the CG openings to the anime, and the games, don't stick out nearly as much as other manga/anime that get translated to 3D. Because Araki already draws three dimensionally.