Quite often when we begin a story, even as the writer we may have no idea what direction it is going to take. Most of the time, we come up with a story because our imaginations have been suddenly sparked by an image, a situation, or even a feeling; only rarely do we have an entire beginning, middle, and end all lined up to fit it. Our stories have minds of their own, and when we let them loose, they will eventually start writing themselves. It isn’t until later that the details begin to fall into place.
Pick a favorite line or phrase from a favorite book, and use it as the first line of your story. Trust yourself to uncover a tone, a situation, and a character from those words, and watch your story play out from there.