Worldbuilding - Today
Now that you've established everything which has happened in your world's past, it's time to consider the present. What is the state of the world? Who is in charge? Who/what are the world's big power players? And most importantly, where do your player characters fit in your setting?
Cover partially in the Society section, the current state of religion is incredibly important. Consider the state of real-world religions: Christianity largely dominates the "West", while Islam dominates much of the "East" and "Middle-East", with quite a bit of overlap. Christianity went through a long period of sectarian violence (Catholics vs. Protestants, etc.) which has mostly died out today, but Islam still faces considerable sectarian violence throughout many parts of the world, especially in the Middle-East. These conflicts have long-standing effects on the world: Much of the USA's culture is defined or at least influenced by its protestant roots.
In fictional settings, religion may work very differently. Depending on the exact mechanics of deities (or lack thereof), religion might be a constant which remains unchanged for millenia, or deities might rise and fall every few years, causing considerable turmoil in one way or another.
Where people live is very important, since your players will generally be one of those people. Populations grow where the local geography and climate support it. Cities like Las Vegas springing up in the middle of an unlivable desert are recent phenomena; for much of history, you needed to live somewhere that had ample food, water, and land to support its population.
Most of the real world's cities exist where they do for the same reasons that cities have formed for all of human history, and serve as excellent examples. A city must satisfy a handful of key needs to form, and the degree to which a location can satisfy those needs often determines how large that city will grow.
- Food: Food is crucial. Until very recently, transporting food was extremely difficult, so you needed to grow food very close to where you lived. Most people produced their own food (subsistence farming) for most of human history. Even when humans moved into cities, a lot of land within the city was still dedicated to producing food.
- Water: Like food, water has been very difficult to transport en masse for most of human history. Much of Rome's success can be attributed to their aquaducts, and the growth of modern real-world cities like Los Angeles is similarly reliant on huge effort expended to transport potable water.
- Safety: Though it's less of a concern in the modern world due to the massive change in the mechanisms of war since World War 1, safety was a crucial factor for most of human history. Cities needed to be located somewhere defensable so that they could repel whatever forces might make the city unlivable. Smaller cities generally only need to worry about natural forces like floods, storms, and volcanos, but larger cities also need to be protected from outside militaries.
- Accessibility: Sometimes in conflict with the need for safety, Accessibility is the ability to travel to and from the city, most often for the purposes of trade. The ability to trade allows a city to grow much faster than a city which grows soleley based on what it can produce. Because the most efficient way to transport goods in bulk has been by water for all of human history (Again: "in bulk". Planes are faster, but boats can carry considerably more at much lower cost), major cities typically form on coasts and at or near the mouths of major rivers.
I like Seattle as an example of how and where a city forms. Seattle is surrounded by fertile farmland. It has plenty of water from rivers, lakes, and obviously a huge amount of rain. Puget Sound provides an excellent natural harbor, protecting the city from tsunamis, storms, and providing a large geographical buffer against possible invasion by sea. The Cascade mountains to the east provide another geographical barrier against invasion, and the dense forests throughout the area make it difficult to traverse by any means except by established routes. While these barriers can make it difficult to reach Seattle, Seattle's location also made it a crucial harbor during the Alaskan Gold Rush, allowing ships to safely dock and resupply before continuing, and allowing Seattle to grow into one of the most important harbors on the west coast. Tacoma, located south of Seattle, is another port which formed for the same reasons, but didn't grow as much as Seattle because rail lines ran to Seattle first, providing additional accessibility.
Governments, Nations, and Power Centers
The existence of nations and governments in various forms defines the political landscape of the world in many ways. While borders are often unfortified, they often have distinct cultural boundaries. The relations between nations also informs the behavior of those nations, and the ongoing events in the world.
Power centers don't necessarily need to be nations or governments, depending on your setting. Depending on the size of the setting, a power center might be a huge organization like the real-world United Nations, or the "Black Sun" criminal organization in Star Wars, or it might be the boss of the local street gang. Scale is an important consideration, and the influence, role, and nature of your setting's power centers needs to match your scale.
Example 1 - Shadow of Olympus
The biggest figures are the gods, and whatever handful of titans might still be around. Facing these guys should be high-level quests tackled by heroes whose names will live on in legend forever, like that guy who decapitated Medusa to petrify a titan whose name I can't remember.
Below the gods there are still human power centers. Kings of major city-states (and the Persian-equivalent region) will have considerable resources and influence, likely enough to occupy low-level characters. The city-states are nearly always at war with each other in one form or another, unless they're working together to fight the Persian-equivalents. This presents a sort of long-term churn where the general state of things is relatively stable so long as someone comes along to kill any particularly major monsters or suppress any abnormal military threats which might seek to upset the balance of power.
Example 2 - Space Grease
Humans are in space! The government exists in kind of a vague sense, but since Space Grease is about fast cars, robot girlfriends, and sticking it to "The Man", generally the only setting-wide power players won't matter to the game. The police might make an occasional appearance to spur a car chase or something, but the most powerful figure players might encounter is more likely to be the leader of a local gang or social clique of some kind.
With space travel easy, cheap, and relatively safe, human life is mostly devoted to recreation. As such, characters will likely live their lives going from thrill to thrill, sturring up trouble and excitement wherever they can find it. Bits of society will be orderly and productive, but those will generally happen in the background of the setting.
Example 3 - Heroes of Tonesvale
Tonesvale can be a self-contained setting. The characters don't need to concern themselves with influences outside the city unless the story specifically requires it. The Mayor could be the most powerful person the characters ever encounter, and wether or not he is a super might be a major plot point. The mayor can change frequently for no explained reason (annual elections? frequent corruption scandals?) which gives lots of room for the balance of power to shift back and forth.
Other government officials might make for interesting figures, too, like a police chief who can transform into a bloodhound to track criminals, or a corrupt detective who frames supers on the police force. There's also the supervillain presence, which can have its own power dynamics.
Since Heroes of Tonesvale is a present-day alternate world, people live and act in much the same way that they do in the real world. Kids go to school, adults go to work, people use the internet and cell phones, and there's two coffee shops on almost every block downtown. Your Barista might have wings or heat coffee with laser vision, but other than that things are relatively normal.