Begin your story like this:

            Paula stepped closer to the tiny store, driven by a once-familiar smell.

            You can change the name, the tense and the setting, but the heart of the story has to be the smell.

            First, decide the cause of the odor. Pizza? Baking bread? Flowers? Rotting food? A dirty body? The smell can be pleasant or not, but must remain the focus.

            To make things interesting, have more than one character so that the discovery of the smell can be discussed, as well as whether or not to pursue its source. Tension through dialogue would add interest.

            The characters will share their reactions to the smell. What for one might be tantalizing, for the other might just be nothing special.

            Have fun with this one.