When world building and designing, you have a few options. First, there is the Top Down option. This is the option that most professional game companies use. Then there is the Bottom Up method, which many GM’s use to make a world for their game. There is also the option I use, which is a bit of both and in no unified order. There is a fourth way but most do not consider it true world building as it is building dungeons alone. Before we talk about the way I do this we will talk about the other ways.
As stated earlier, it seems Top Down is the game industry standard. You start with looking at things from the highest point first. Which for most games is a planet. Then you go to the continents then the country/kingdom, then finally the city or town. When doing this you are plotting out things and tying them to the overall world. The advantage of this way is things are unified and universally consistent. The disadvantage of this way is that it is hard to come up with everything for an entire world.
Bottom up is the way I feel many GM’s do world building. You start with what the PC will interact with first. So you get to think locally, the starting hamlet or town, then a few outlying settlements and towns – places the PC can get to easily. Once you have that, you get to figure out where the kingdom ends. Once you have a few kingdoms you will have a continent or close to one. Then you can think of starting all over if the planet has multiple continents. The advantage to doing things this way is you are creating what the players want to know about. The biggest disadvantage is adding elements will be hard to do if you don’t have the bigger ideas finished.
Now I will just say a few things about the dungeon setting as a design style. This way is actually the oldest of them all. Thanks, Gary Gygax. See the original Greyhawk setting was built on towns around dungeons. Elements of the greater world history was buried in the dungeons. So this is something to keep in mind when doing things in your world. History should be uncovered in unusual places as well as the ordinary. I don’t really know what I consider to be the pros and cons of this way of world building.
With all of those out of the way now I will tell you how I design a game world and the pieces that I find to be important. I like to have a few big things figured out first. Those are the continent or the biggest part that I want to run a game in as well as the religions. The reasons for starting with those is very simple. The landmass gives me a set space to work in and the religion is because so many of the core classes in fantasy games I play have tie-ins to the faiths. Then I will do a few gross ideas for land features like mountains, rivers, and large lakes.
Once I have those things, I will start with a town or city that the characters will be starting in and do a few people and places for the players to interact with. After that I will place a few different adventure locations near by and hints for where some of the next towns are. This is something that can be done in a week or so to get a new group off and adventuring quickly. Asking players what they would like to see in town is an easy way to flesh out sections of town. An additional trick you can try is asking the players what is special in town to them. Once the initial town is finished then it is time to do a bit of detailing on the outlying towns.
While working out the basics you should be doing some idea crunching on the story you are wanting to tell. But that as they say is a topic for another time.