Back in 2005 I participated in a screenwriting workshop offered through Sidewalk and taught by the wonderful Elizabeth Bradley. Elizabeth gave a wonderful talk about the importance of a hook. Let's see if I can convey what she so artfully said back then.
She used the following example:
The movie Brave Heart is in essence the story of Scottish Independence. But the hook, the thing that made it so captivating was William Wallace with his bright blue war paint and bleeding heart. And the two women (the quaint Scottish girl in the village and the royal French hot lady) in William Wallace's life are two characters that draw you into his story. Without them the story wouldn't be relatable; only politics and genocide.
There has to be a reason for telling your story, your particular fantastical tale, or murder mystery. What makes your story worth reading?
There needs to be unique drama and conflict. And most importantly the protagonist must change. We're not talking about their hair color or just making a new friend. Their very soul must be inexorably affected by the conflict you construct in your story. If your protagonist is the same at the end as they are in the begining, then the protagonist isn't compelling or interesting.
Find that hook or angle that makes your romance or mystery or YA intriguing. Are you going to write a political diatribe on Scottish independence or are you going to weave in the story of a brave man with a torn heart who captivated and moved the down trodden Scottish people towards independence?