Your character is not unique because of its race, class, abilities, or mechanical scores. Why? Because anyone else can duplicate. Rather, your character is unique based on the storyline you create for it. Avoid clichés like "my family is all dead murdered by [insert race] and he has a lust for revenge" or "my barbarian speaks in the 3rd person and likes to bash everything." Add some flavor.
Torg of the Hawk Clan is embarrassed that he cannot read as well as his friends and he cannot seem to grasp Dragonchess when everyone else knows the moves. While he pushes himself to excel in honor of his deity in physical arts, there is a part of him that admires the shamans of his tribe, normally regarded as the weakest. As a result, Torg is hesitant and reserved around those who remind him of his tribe's shamans. As a GM storyline (for sandbox campaigns), Torg may unknowingly have a sibling who became a shaman as they are culled from the weak children and not permitted to be part of a family.
If you're in Pathfinder Society and/or playing a one-time session with strangers, don't bother. Few, if any, are going to remember (or care about) your cool background or how you tricked out the rules to do 4d4+12 damage at 3rd level with each attack. But if you are in a campaign that may last, memorable characters have always been the ones who contribute to a good story.