Every person out there has always had that secret dream in the back of their mind that they could live in their favorite fantasy world. The setting of any table-top RPG becomes essential to the campaign and the creative minds of you and the player.
Since I was a wee lass of eight years I have been inventing fantasy worlds. I currently have seven finished world and probably around 12-18 unfinished ones. As a DM this is not necessary, it just so happens to be my hobby. But what is necessary is finding the right setting for your campaign, it being one you create or one someone else has created.
There are tons of places online that you can find fantasy settings. Paizo, the creators pathfinder, have a variety of worlds, many that are very fleshed out and elaborate in detail. They sell books on specific locations as well as large area maps. Most of Paizo’s stuff can be found online for free, so don’t pay until you have checked online!
Many people like me post their work online, at homebrew websites or on forums. These usually are more specific to a certain style of campaign or for specific questing. If you already have a campaign in mind it may be harder to use a homebrew world from someone else. If you do not have a campaign you are set on than using a homebrew world would give you plenty of ideas, maybe some you had never even considered.
If you are one of those people who just needs everything to be original, than these other options may not satisfy your lust for design and control. I am one of those people. Since the beginning I have been running Pathfinder and D&D games on my own maps. This route is tricky though, because the amount of work you put into your world can make or break the campaign.
My players at one point wanted to have a steampunk campaign, but still following many of the fantasy style rules. To find this kind of setting online was nearly impossible, especially when it came down to one that also fit the pathfinder rules system. In this case I had to build my own map and setting in order to fit the needs of the campaign.
The other important thing to consider when deciding between using a pre-made setting or one you create is the kind of work you want to do in preparation. Both require a lot of time and commitment. Using a pre-made campaign requires reading and information gathering about that land and place. As DM you are the one that has to answer the tricky questions and knowledge checks that players make. Therefore you need to have a good base of information about that world or you will be bogged down time wise by having to look things up or come up with ideas on the spot.
With creating your own world, there is a sense of depth that has to be provided for the players. It goes beyond just drawing a map and naming a place. There are a multitude of things you have to consider including geography, politics, economic issues, groups and races, history, technology, religion, and more. Making a map can become time consuming, but it will always be what you need as you are fitting it to your specific campaign.
The setting you choose for a campaign plays into almost every factor of the campaign. It determines the creation, the playable races and classes for the characters, the background and history of the players and the campaign, and the type of monsters creatures that will be fought. The setting affects every aspect of the campaign before and during the campaign and should not be taken lightly.