This is an article I wrote on characterization:
Characterization: Get Real!
If the plot is the backbone of the story, then the characters are the heart. Creating believable characters that your readers will identify with is crucial to a good story. Your characters must have depth, personality and the ability to evoke an emotional response from your reader.
Before you can formulate a riveting story, an interesting character must be devised. Many writers envision the setting first and the people inhabiting that world second. This often results in shallow characters. Developing a character in depth, complete with flaws, will give you a basis for your narrative. It is easier to build a plot around an individual than force that character into unrealistic situations.
Two factors will determine your character – their background and their personality type. Both are equally important and require some thought. Humans all share similar feelings and needs, but how they respond to those depends on their upbringing and their basic, fundamental personality. You need to be aware of these factors when writing your story.
Backgrounds are as varied as humans themselves. Race, culture, religion, and economic status all contribute to one’s development as a person. A person’s moral compass is easily affected by their upbringing, and you need to keep this in mind when creating your characters. A person raised by a loving family on a farm and someone raised on the streets of New York will not react the same! Flesh out your character with a family history, interests, and experiences.
Become familiar with the four basic personality types – choleric, sanguine, melancholy and phlegmatic. They will also determine how your character reacts in any given situation. (“Personality Plus” by Florence Littauer is an excellent book for researching these personality traits.) A bold, first-born choleric would likely take charge in a situation, while an introverted phlegmatic would step aside. You need to be aware of these personality traits in your character or you will find them responding in a dubious fashion.
Avoid the temptation to create a perfect character! People are flawed creatures and the more imperfections and internal conflicts your character possesses, the more intriguing your story. Give them weaknesses, impulses and unresolved issues. Negative aspects of your character might improve and eventually vanish, but this needs to be developed slowly during the course of your narrative. Life altering moments happen for us all, but a sudden change for no apparent reason will be looked upon as a mere plot contrivance.
Characters will always be the drive and focal point of any story. By putting a great deal of thought into your main characters, you will form interesting, relatable people. Once you have established this foundation, you can begin creating an intriguing tale!