Probably the answer to this question is as varied as are the number of reader. One thing that pulls in interest is being different. The mundane is out. Something unique sets aside the story from everyone else. But the readers needs to identify with the story’s elements. Something about it must be familiar. The combination of unique/identifiable seems like an oxymoron but think of some of the great successes.
The Twilight series is a good example. What is Identifiable about it? Vampires. We all know vampires. Yawn! What is unique? This is a love story between Bella (the girl next door) and Edward (the vampire). Continuum, available on Netflix, caught my interest lately. The story is science fiction time travel with the obvious paradoxes, but it’s also a police procedural (aka mystery-thriller) where the time traveler works alongside of a detective on the Vancouver police force. Also, the lead character, Kiera, is not only a high tech cop from the future, she’s a mom and wife, sorting out career-work issues.
Ask these two questions about your story. Why will everyone identify with it? What makes it different from everyone else?