Most stories don’t open with a character’s birth. The majority start much later on, usually on the eve of a turning point in the main character’s life. For instance, The Hunger Games opens shortly before Katniss takes her sister’s place in the 74th games. Divergent starts when Tris’ Aptitude Test is on the horizon. The Lord of the Rings begins not long before Frodo Baggins is given the titular ring by his cousin, Bilbo. What, however, happened in Katniss, Tris, and Frodo’s lives before the aforementioned cruxes were reached? Plenty. (By the way, this is true for every character–even minor ones will have led occurrence-filled lives which transcend the book’s pages. They were not born in a vacuum.) It stands to reason, then, that–akin to us non-fictional beings–each character in your story will have a unique way of relating to the world around them, so shaped by their life experiences. Bearing this in mind, how can they all express themselves in the same way? They can’t. It’s impossible. Mannerisms, facial expressions, posture, gait, and word choice will differ from character to character. It must. This isn’t to say that there can’t be overlap. Rather, each character should be endowed with at least one quality which sets them apart from the rest.