In the world of mystery fiction you need a heroine, a criminal and a victim. Sometimes these descriptions overlap and the heroine is also a victim trying to get revenge. Or the criminal had been a victim in his past and now has a warped sense of right and wrong. Sometimes the victim was a real jerk and got her comeuppance by one of her victims. Or, sometimes it’s quite simple: the hero really is a hero, the victim an innocent bystander and the villain a very bad person.
Whatever the plot, it is fun to dig into the psychology of each character and twist their motives around. After all, we rarely meet real people that are one-dimensional and shallow so why should our characters be? Crafting memorable characters that are realistic is challenging but worth the struggle. A well-defined character can thaw your heart or launch tentacles of fear down your spine. Think Christopher Robin. Now think Hannibal Lecter. Big difference.
Create your characters to make a difference to your story, be it good (that would be Christopher) or bad (that would be Hannibal). Both are memorable in their own special way. Personality traits should be strong—or weak—depending on their part in the plot. Quirks are fabulous, after all, most people that we meet have their own quirky behavior whether it’s talking with their hands or constantly clearing their throat or incessantly hugging or touching other people. Don’t hesitate to take your characters to the max; they’ll be a lot more memorable that way.