Sometimes when we start building a setting, it flows easily. Many settings already have a shorthand that we can use, like fantasy or cyberpunk, where we don't need to detail much about the setting. We can just drop our characters into the setting and move along. We are all on the same page.
But sometimes we try something new, we build a world from the ground up and we get lost. Here's a helpful worksheet to keep you on your path in Setting Design. I named it alpha as it will no doubt get upgraded as time goes on. But so far this has really helped me to keep focused on my settings.
GenreFirst you should pick the genre of game you are playing. Is it Fantasy, Historical, Western, Modern, Cyberpunk, Space Opera, or Hard Sci-Fi? Is it a combination of these genres? Make a note and start looking up these Genres on TV Tropes. Tropes are the shorthand of any genre and using these will help your players get a quick feel for your setting. They will also help you in filling out the rest of this worksheet.
Trope CharactersWhat are the typical, iconic characters of your genre? Who are the type of people that wind up in your trope's adventure. This will prepare you for the types of characters your players will want to play and it may also point to some new rules you may have to add it your setting. For instance, if your setting occurs in Victorian style England or the universe of a Dune styled empire, then a character's Status becomes very important in social encounters.
Trope VillainsWho are the heroes likely to go up against? What are the typical villains that will populate your setting? List them out. Just rough character types here, you don't have to flesh out each villain. Just list things like: Pirates, Mad Scientists, Corrupt Religious Figures, etc.
Trope LocationsSome settings are more about the environment than the characters (like Alice in Wonderland). Even if it isn't, locations can be inspiring and set the tone of your setting if done right.
Magic?Pretty basic. Will your setting have magic and what will it look like? What are it's limitations? What do people think of it?
New RulesWhat new rules will be required to give your setting that Trope feeling? In horror games this might take the form of sanity/fear rules, Status rules as mentioned earlier, or things like starship construction. The danger here is that you might go overboard or add too many new rules that just bog down the game. Design only those rules systems that your setting requires. Try not to add more than a couple of new Edges or Hindrances. Often times what is already in the rulebook will cover what you may want to do.
Also, try to keep the new rules simple. You don't need more complications in your life.