Not all games have to be about telling a story, of course, though I did get the impression this game jam wanted games of that kind. I think the most helpful way to help players create story is to give them a something to base their characters off of, and something to help them decide what their relationships to other characters are. These are usually the first choices you make in a game and it's a lot harder to make something up from a void than it is with a seed, a prompt or idea to inspire you. This can often be as simple as a list of evocative words or phrases to choose from. Many of the events in your game could serve as prompts to build scenes or narration from with a little more guidance, likewise so could the stats and type of country be a basis for character creation.
Sometimes you make the mechanics for a game first, and figure out what kind of story they create, and sometimes you come up with what kind of story you want to tell and make mechanics that do that. Nothing wrong with the former.