Here's one thing a thesis shouldn't be: an observation. Unfortunately, you can't just point out something true about a novel or short story, and describe that something for five paragraphs. Or you can, but only if you want to see "OK...annnnnnd?" or "So what?" scribbled in the margins of your paper.
Coming up with an observation, as this Sparkler has, is a good first step:
In both the novel Life of Pi written by Yann Martel and the movie The Black Stallion by Carrol Ballard, the protagonists start their lives as innocent and naive boys but grow up mentally with the help of experience, heart built relationships and actions that show they are different from most boys.