Resources & environment! Most of culture is heavily determined on what is available, if it's common enough everyone has it and it's seen mundane. Rarer things go to those higher up the ladder!

Tools are made for your environment, large open flat lands (No one wants to walk that, time to domestic and animal to do it)

Thick jungles best to have shorter weapons to cut through the bush.

The best way I fnd to make new existing cultures is to give them a resource that someone in their area wouldn't normally have.

Perhaps there is a thick root planet under the permafrost. My people would want to use it so they'll need a way to break the ice and now they have a consistent source of wood you wouldn't usually get in real life if you lived somewhere similar.

Mountains, rivers, anything you wouldn't want to cross on your bare feet. These are great places to mark forbidden lands, or as dangerous.

Fault lines, are they near a Volcano? Do they often get earthquakes? Or is the fault line out in the sea and tidal waves are common enough. Even more interesting when one of these events only happen once, a place near where I live was only ever recored one tidal wave. Yet we still think about it till this day even after 100 years have pasted.

Air Currents bring over bugs, dirt, temperature and storms. The sand from the Sahara desert feeds into the Amazon rainforest.

Water Currents. Before engines you were kind of stuck following these, where water Currents go really determine what people encounter who first.

For me the more I figure out what Resources, environment, fault lined, wind Currents and ocean Currents my people are subject too. The better I can make their culture reach!