Stories thrive on specifics, the key elements that make this plot work and interest the audience. Look at Romeo and Juliet, that is a story of two lovers being kept apart by circumstances. That is Romeo and Juliet’s core, but it is also the core of West Side Story and many other stories ranging from Romantic Comedies to Tragedy to Action Thrillers. All that changes is the combination of the elements you use to make up your story.
I bring this up because recently I had a conversation about Gamemastering Style and there was a statement made that when a Gamemaster asked what you wanted to play in, they wanted specifics like you were going to give them an answer to an essay exam question. Problem being, most players do not know the specifics on what they want to have happen, instead providing you with themes like ‘I want to be a hero’ or ‘I want to find a lost treasure’ or ‘I want a mystery’, these are the cores you can build your story on.
How you choose to integrate the player decisions will differ from GM to GM as some will script out scenes and others will try and let it all occur naturally, but the way I do it is to start with a story I know has what the players want. They want to find a hidden treasure, we have Treasure Island, Road to El Dorado, Indiana Jones, Maltese Falcon, Relic Hunter, Uncharted, Tomb Raider, there are so many stories with so many elements I can take for set piece moments, NPCs, locations, and so forth. I will start simple with the elements being taken out, by begining with designing NPCs, but you can break down the entire story this way and pull the story elements from one story and use it in another. I will show this in a later example, but Da Vinici Code, Indiana Jones and Monty Python all had a search for the holy grail to some degree.
For example, perhaps your opening takes place in Rick’s Bar from Casablanca with a bartender based off Long John Silver’s cook from Treasure Island, and the waitress working the place has the rough and tumble personailty of Calamity Jane taking no sass from the customers. These personas are all kicking around from the works we take in, so how do we call them out on command?
A few options exist. One I suggest is taking a few index cards and writing down basics, the appearance and personality and any specifics like quotes or things you need to get into character. Make at least 20 to 30 for variety. Put on some movies and write them up as you go, just beware of duplicates or those so close they could be duplicated. You are going for the ‘Random citizen from town’ effect if you pull one. You can also do this for locations, if you want to be able to pull locations at a whim as well.
Another example is to look at TVTropes which in this example of people about town, it does almost all the work for you as it categorizes almost every fictitious character in some way. You could use your own town or any fictional town you’ve seen in movies or television. Just make sure to give everyone something interesting about them, to give the players a reason to interact with them or at least something to set them apart from others.
By having a list of elements on the go for people, places and some story hooks, you can easily try and create an encounter on the fly to give people the elements they want without having to worry about pre-planning everything.