Every writer strives to make his characters believable and as real as possible to the reader. This can be done in several ways. The character can be given certain traits. He can have a nagging cough, or repeatedly push his glasses up on his nose. I once did a story about a character that pushed his glasses up on his nose. In normal circumstances he would use his index finger, but if he was annoyed or angry, he used his middle finger. A character can speak without using contractions to make them seem aloof or arrogant, or speak using poor English if they are uneducated. But all these character traits do more to make the character memorable and identifiable than believable.
To make characters believable, they must exist outside of the story itself. They cannot be there simply for the moment they are in the story. They must have a back story and even a future. This does not mean that the back story has to be presented to the reader. The biggest criticism I have received is that I have too much back story for even my minor characters. But the characters must have a life in the writer’s head outside the story itself. If they do not exist for the writer, then they will not exist for the reader.
In my novel, In The Sticks, there is a paramedic who appears briefly three times. She has about two dozen lines of dialogue and is not essential to the story. She is a tough, crude woman and not very attractive. I know that she was abused by her father and was sexually promiscuous through high school, sleeping with anyone who asked and sometimes several partners at the same time. When her nerdy future husband asked her out, she had no expectations that it would be anything but a one-night stand. When he showed up the next day and found she was having her period so they couldn’t have sex, he stayed around and continued to come over daily. She was so blown away by a man wanting to be with her for more than just sex that she fell madly in love with him. Eventually she will go back to college, get a degree and get a job with Human Services to help other abused young girls. None of this is in the book, but by knowing her back story I know how she reacts. She becomes real to me and hopefully to my readers.
Also in the book is a mentally-challenged man named Herbie Wurtz, who is very essential to the story. His mother is in the book for about three pages. I know that Mrs. Wurtz was the wife of a farmer/rancher. She raised two kids who went off to college and then onto careers of their own. Mrs. Wurtz became an alcoholic. One night when she was very drunk she got pregnant. She did not realize it and continued to drink. Herbie was born with fetal alcohol syndrome (for those of you who have read the book that is Herbie’s affliction.) Devastated by what she had done to Herbie, she quit drinking and became the head of AA in the county. She has lung cancer, although she doesn’t know it yet, and will die within two years. I have no intention of using her in any future story, yet I know all this and more about a character that has about ten lines of dialogue. By knowing her, I not only know how she reacts to situations, but I know what makes Herbie tick.
When my wife read the final draft of In The Sticks, she often asked me, “Who is this supposed to be?” referring to one of the characters in the book as if it were someone I knew in real life. At that point I knew the characters were believable even though they were created entirely in my mind, because to me they did exist.