Once you learn how to understand and apply historical materialism and break out of capitalist canards like the myth of barter, it becomes much easier to come up with the things that make societies feel evolving, nuanced, and alive: internal struggles, subcultures and countercultures, political movements, economic bases, social mores and customs. That, plus having a variety of real-world examples to draw from to avoid falling into the trap of capitalist realism.
To this day my favourite instances of world building are Disco Elysium and Elden Ring.
Not much to say about Disco Elysium. It's writers are Marxist.
While Elden Ring creator is most likely not a Marxist, his work (Dark Souls series, etc.) grapple with concept of epochs rising, waning and coming to an end. A common theme is that there is an ever pervading atmosphere of stagnation (in the japanese sense), decay, rot, and major actors of the world are either trying to keep the flimsy scaffolding standing while others are trying to being the current age to an end so that a new one may begin. It stands in contrast to how liberal media and people seem to not know that history has gone on for longer than since yesterday.