One way to use coincidence and make it work is to have nothing turn on it. Coincidences feel illegitimate when they solve problems. If the story doesn’t benefit from the coincidence, it’s simply pretty and suggestive. Another way to make a coincidence work is to begin a story with it. Make it the reason there’s a story to tell in the first place. A third is to establish that the community in which your story htakes place is one in which coincidence is part of the landscape. People in my town, New Haven, Connecticut, revel in coincidence, and we claim it happens here all the time: you know everyone in more than one way. Maybe this is true in all cities of a certain size—small enough that the barista will turn out to be your office mate’s daughter; large enough that you’ll be surprised.