When writing a novel, full-bodied characters will do more to add believability to your story than anything. Through them, you will bring your story to life. You can do several things to create characters who will jump off the pages. They are:
1. Write a resume for each character. In it include information similar to what you would put in your own resume when preparing to apply for a job. It should be a detailed description of the person's educational and work history and accomplishments. If detailed, it will provide the structure for a character sketch of that character. At the end of the resume, write the details of a few incidents from the characters life that might apply to your story.
2. Physical description. We don’t always describe characters in detail to readers. Sometimes we just leave it to their imaginations. But for you to know your characters, it is important to be able to visualize each of them in vivid detail. Include in the physical description of each character: height, weight, body type, hair versus no hair, hair color, eye color, etc. Those are the basics. It's important to write them down and keep them straight. You don't want say someone can change a light bulb without a ladder if he isn’t tall enough.
Beyond this basic physical description, you'll want to get a clear picture of physical characteristics that set your character apart, such as walking with poor posture, long painted fingernails, the fact your character always wears a sun hat to keep the sun away from sensitive skin, a special piece of jewelry your character wears always, etc.
3. Quirks. We started addressing quirks a bit in the previous section. The more detail you have in mind about quirks of your characters, the more real and distinctive they will become. But don't go overboard -- too many quirks and your characters will turn into caricatures.
4. Likes/dislikes. Make a list of your character's likes and dislikes. What makes your character happy and what makes him sad or angry or embarrassed, etc. This list will help you know instinctively how your character will react to circumstances that arise in your novel. Also, list any allergies, chronic conditions, etc., your character might have.
5. Hobbies/talents. Make a list of the talents your characters bring to the table. If your reader knows that your character works out or was a runner in high school, the reader will expect him/her to do well in a chase on foot. If your character is a good cook, it may add to your story that people drop in on her just to get a taste of her latest cookies. This may not add an integral point to your story, but it'll help to round out your character.
6. Shortcomings. What are your characters weaknesses? Often the weaknesses will make the story more interesting. You don't want characters who don't have any faults. That's too boring.
Put all these characteristics together when you write your novel and the readers will find them intriguing and believable.
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