I always have the concern that what I find interesting is not interesting to the rest of the world. How does a storyteller make sure his story has universal appeal?

That's a great question. Many of us have been there; We have a personal or a family story that we LOVE.  Just the thought of the story makes us laugh. Now we have to ask the ultimate question; will the audience love it? You will never know 100%, but there are some ways to evaluate it.

What is universal appeal? This usually comes back to an important question regarding your story: what's the story about? What is the theme or thread of the story? Beyond the characters and events in your story, is the theme something that's important or of interest to MOST people. 

What is the emotional arc? Is it something that most people experience; a struggle; a joy; an anticipation; a fear? These things are generally experience by the majority of people in the world. Stories from cultures other that our own demonstrate this. Aladin's hope for riches, and longing for the "un-attainable" mate; the turtle's desire to win the race and "triumph" over the bully rabbit; the abusrdity and foolishness of stories from Chelm or other knucklehead, noodlehead or Jack tales; These are situations/feelings that most of the universe can relate to.

Two examples: Doug Bland's stories of his Grandmother have universal "themes" of wisdom and close relationships. People often feel as if his Grandmother is LIKE their own, or wish that theirs was like her. Liz Warren's Horney Toad story shows us the thrill of a girl who wishes to "own, have (perhaps control) a small "free" animal as a pet, and provide it a home." She shows us the wisdom of her Grandfather (or was it your Father, Liz?) who explains that the horny toad has parents who may be missing him. These are universal themes and emotions.

Antonio Sacre said, "Choose a story that matters to you and then ask if there is anyone else besides friends and family that needs to hear it? 

Are the characters appealing or likeable? Beyond the fact that it is your brother, or uncle in a personal story, are the characters ones that most people can identify with in one way or another? What archetypal characters might they be like? Is there some way you can make them relatable? The oldest, the middle and the youngest are archetypes that may fit the characters or people in your story. Will helping to expand and clarify their roles allow people to relate more to them?

Here's a rule of thumb: If it's a story about your Uncle Joe that the family "retells" every Thanksgiving and the family laughs hysterically as they recall the events - it may not appeal to others. Or...can you tell it in a way that it will appeal to others? Try telling it to a few "others"; friends or colleagues that are not privy to the everyday peculiarities and connections that the family members have to Uncle Joe.

And one must also assess your particular audience (as always). Is your story relatable to the demographics of your audience? Will they relate to it in a positive way? Perhaps the themes are not in line with their religious, political or cultural make up. If not, then it probably is "not quite" universal, and should not be told to THIS section of the universe.

I hope that helps, Mark. Who's got the next question?