So if you read the summary of this story you would know about Epigraphs.  The definition of a short quotation or saying at the beginning of a book or chapter, intended to suggest its theme, and it can be used to help, or hurt a reader, and can allude to another's work, whether it be a novel, song, or otherwise. They don't even have to be real quotes, they can be something a character says, or just something random you wrote. TFIOS has a fake epigraph using a quote from an important novel in that story, An Imperial Affliction. 

For example for my book Survivor, Hope is a major part of the story so this is the Epigraph: "Once you choose hope, anything is possible." In addition, in every chapter I have a quote that acts as a mini epigraph specific to that chapter, giving the reader a hint about what is to come. 

Epigraphs are considered throughout a novel, and get the reader thinking before the story actually begins, usually. That is why Epigraphs are really important. I would like to see more Epigraphs here on Wattpad, so I'm here to help! 

More info here: http://thewritepractice.com/epigraph/