These are my thoughts on world building for a fictional world. There will be a skews towards worlds in a table top role playing experience, and moreso towards a fantasy setting.
cause and effect
A fun thing to think about with world building is what you would think would fall out of it. There are basic decisions to societies, fantastical or not. When you introduce something to your world, you’re making it different from the world we live in now. No matter how remote your world is from our current world, the created world will be defined by how it is different from our current one. When you change something about the world, think about how it effects the major aspects of society, the bestiary (if applicable), and even the world’s geography. It might not shape all of these things, but it should influence at least one. I would even go as far as to say with a little thought you can make your world change effect everything - some in minor ways and others in major ways.
eating and drinking
Creatures generally need to eat and drink to live. Even in a sci-fi setting, robots would need some kind of power source or even lubricants to keep the parts from wearing down. How do the people of your society gather food?
societies and their food sources
A hunter-gatherer society roams the land - typically in a known rotation that follows favorable weather. Staying in one place too long can put too much of a hardship on the land’s resources. Plants are picked clean, and the game is driven out or wiped out.
In an agrarian society, most of the food comes from fields of food that is grown and tended, and then later harvested. Agrarian societies might celebrate the harvest. They can also thrive in places with harsh winters, though such societies would have means to store their food, and likely have winter activities - something different than farming when farming just doesn’t work. Though it could be preparing for next year’s crops. Agrarian societies generally struggle in places with steep hills or overgrown vegetation. Agrarian societies might be dominantly farmers, but efficient farming techniques means a society can support specialists. People who guard the farmers, who can study things such as chemistry or the movements of the stars. A knight cannot swing a sword without a blacksmith to create the sword, the miner to gather the iron and coal, and above all else: food to feed them all, grown by a farmer.
Some societies might trade their goods and services for food - modern cities do this today in essence.
Not all farming would be fields of wheat as far as the eye can see on a sunny day. Wood elves might have farms but not like how you and I would see it. Perhaps their closeness with nature means the food almost comes to them. Each elf might grow plenty of food near their individual dwellings. Such things might be permaculture such that the elf needn’t spend a majority of their existence tending to the crops. It would provide variety and to many non-wood-elves, it would just appear to be beautiful, lush nature.
Underground creatures might harvest mushrooms.
hunting and populations
Hunting beasts for food is a reasonable supplement to cultivated food, but generally it is not sustainable for moderate numbers of them to exist in one place for long. Consider 20 wolves and how much meat they’d need to eat in a single day to just break even. With that many kills, consider also how alert the prey would become lest they die off. In the real world, populations of predators and prey fluctuates and can become unsustainable. Generally creatures have behaviors or aspects that help regulate this a bit - though they are always imperfect. For the examples with wolves - there can only be one alpha with a pack. Contending alphas that don’t fall in line must form their own packs - and with that comes territory shifts. The effect is the wolf packs spread out. In circumstances of overpopulation they could even spread into civilized areas. These are areas wolves generally would not go because the protectors kill the wolves, or at least make credible threats to kill them. But when one needs to eat and the food is scarce, one becomes more daring or starves.
Most creatures that exist by nature rarely pick starvation.
the value of food producers
Are food producers considered honored members of society? If so, how important is it for a given child to grow to be a farmer? Are children a means of producing farm hands, and therefore a fertile coupling is a cherished thing?
Even societies with lowly peasants are highly valued - just in aggregate. No individual peasant is valuable. But when considering them in bulk they become assets that lords will make power plays to seize ever greater amounts of them, and therefore more resources to sustain an even more powerful civilization.
power
In this context, power is simply the ability to make decisions. Who gets to make the decisions in the society? The wealthy? The honored? A class set by birthright? Warriors? Each of these can have profound effects on how the society is structured. Even more exotic forms could be power that goes to external entities, such as a more powerful nation that has installed a puppet government or even rules it directly. Perhaps, above a normal power structure, monsters treat the humanoid population like cattle and feast upon them every year. A tribe might have to sacrifice a virgin or some other life offering.
wealth as power
pause the bias
I want to start here by talking about the real world and our feelings about money. Most of us have jobs or perhaps support someone with a job, which is work in its own right. We might feel like money is too often abused and its effects seem more harmful than good. For the purposes of building a society in an imaginary place it can help to suspend our biases (no matter how deserved they might be) in order to build a convincing and richly detailed society. Save the money-as-evil stuff for your villains. Also consider that we don’t have the same angst towards feudal societies that implicitly understand to be very flawed, but it doesn’t stop us from creating very entertaining stories about princes and princesses.
what constitutes as wealth?
Money makes the world go ‘round. Having a high amount of money or even non-currency material with some economic benefit constitutes as wealth. The wealthy generally see things as potential investments, or a waste of an investment. While one may not have lots of money in the coffers, one could have many enterprises that bring in lots of funding which gets invested back into the original enterprises or new ones - in this case the enterprises themselves are the representation of wealth. These enterprises could be textiles, medicine, education, mining, lending, or even estates.
“Old money” represents monetary gains made generations ago that the rich can coast off of today without necessarily being as mindful or involved in how that money is replenished - though parents would be negligent not to teach their children how to take over the family business and survive in the world that they themselves also likely inherited.
In the real world, Sportsball players become rich but without knowledge on how to grow, invest, or create trusts out of their money, their supply can dry up as quickly as it was earned. In a fantasy world this would play out as adventurers - people whose skills amasses them enough fortune to catapult them far out of their financial classes - but they will sink back down without the know-how to keep it going. This is what being born into wealth buys you: The tricks of the trade to keep one’s wealth. Just like Sportsball players in the real world, adventurers can learn some of these tricks through advisors or perhaps they are quick learners with a knack for high-level money handling. Your society should probably have very few of these or the world may seem unstable, unconvincing, and most importantly: it dulls the flavor of a good rags-to-riches story.
stuff wealthy people like
When one has enough money one can use it in an exploratory fashion. Wealthy people can invest in a portfolio of endeavors and still have enough to dip their toes into more risky prospects. When a prospect begins to show some promise, the investors can push more funds into it to make their investment grow. A wealthy person might think themselves cold and calculating in their investments, but their biases are revealed by what they invest in - especially when it comes to investing in the esoteric.
Wealthy people structure their lives around wealth. They make it a point to display their wealth to others. People who are close to a wealthy person may offer the wealthy person favors in order to gain contracts, investment, etc that the wealthy person can provide. But they can’t do any of those things if they don’t know the person is wealthy. Being outwardly wealthy also means one can be in the company of other wealthy people. This makes for good opportunities, and family arrangements can proffer for financial allies in the future.
This all is why status is so important to the wealthy. In fact (at least in story writing - this author isn’t at all wealthy), for wealthy people the day to day management of money becomes unimportant and the projection of status becomes far more important. Hire people to do what hired people are good at: Jobs.
wealthy people calling the shots
When wealthy people call the shots, it’s just as political as any other gathering of power. There is limitless posturing, maneuvering, allying, proverbial backstabbing, lies, and damn lies. A group of wealthy people might agree to invest their funds in some portioned amount towards different causes to help run the society. Without roads, everyone suffers. Cities need waste management, protection, means to put out fires, etc. A ruling guild of merchants will be no stranger to any of these aspects - no matter how menial or dirty these things might be. Remember: Wealthy people just hire folks to do this dirty work. Managing the work from afar is just more of their status showing.