Whenever I come up with a great story, I first write the synopsis with as many details as possible but try to keep it within a paragraph or two. The next step is one of my favorites, the mind map. This is where you just write everything that comes to mind about the story and categorize them together later. By now, you should have a good idea about the characters you will need to tell this story effectively. When I create my characters, I try to make them as believable as possible and avoid the stereotypical tropes overused by so many.
The protagonist is not the strongest, the fastest, or the smartest, and he does not always prevail in situations. He has flaws, makes mistakes, and chooses the wrong decision because sometimes he follows his heart instead of his head. This goes for all the other characters as well. Their decision-making must be driven by their motivation to be believable. Their motivation has got to fit their moral stand and beliefs, which also define their desires. If a character's morals despise evil acts, they would desire to accomplish goals without committing evil acts. So if the only choice was an evil action, they would struggle with the decision and may make no choice at all, or hesitate, make the choice that is in opposition to their morals, and emotionally or psychologically suffer from it.
Keep things like this in mind when creating characters. Your readers will thank you!
Determine the character's role
Decide the basics
Define the physical attributes
Describe the emotional characteristics
Build a background
Decide the role they will have in your story
1 DETERMINE THE CHARACTER'S ROLE
Choose how your character fits in the story by choosing from the following list. (hint: your character may be more than one of these)
Protagonist: the main character (hero)
Antagonist: the "bad" guy
Sidekick
Orbital: neither protagonist nor antagonist, but prominent in the story
Love Interest
Confidant
Narrator (either a Character in the story or telling about the story)
2 DECIDE THE BASICS
Consider your character, and determine the basics as if you are examining them in person. Ask them questions, and get answers. Remember, regardless of their role, every character has good and bad about them. Strengths and weaknesses. If you struggle with basics, there are plenty of tools that will auto-generate names, nicknames, ages, etc. I enjoy this part because of all my years playing role-play paper and pencil games. Regardless if it is Dungeons & Dragons, Heroes Unlimited, or TMNT, there is a process of character creating that must be performed.
Full name
Nickname and origin
Age
Where they live
Where they are from
Occupation
Income
Skills
Talents
Hobbies
Habits
Best qualities
Worst qualities
Passion
Best friend
Worst enemy
3 DEFINE THE PHYSICAL ATTRIBUTES
How does this character look and sound? It may never be written in your book, but these details will help you form and resolve different situations and conflicts.
Height
Weight
Body type
Fitness level
Hair color
Eye color
Glasses or contacts
Ethnicity
Species (for science fiction)
Distinguishing features
Quirks
Handicaps
4 DESCRIBE THE EMOTIONAL CHARACTERISTICS
The emotional/psychological characteristics will establish the core belief system of the character, which in turn determines their morals and motivation. A simple internet search will turn up various sites for randomizers if you choose.
Personality
Attitude
Introvert / extrovert
Spiritual worldview
Political worldview
Weaknesses
Motivations
Fears
Internal struggles
Secrets
5 BUILD A BACKGROUND
Our past, education, family, economic status, and environment shape who we are, what we believe, and what we are willing to do in life to get what we want.
Birthplace
Family members
Birth order
Childhood
Education
Accomplishments
Failures
Trauma
6 DECIDE THE ROLE THEY WILL PLAY IN YOUR STORY
What does he want? (a novel-worthy goal or challenge)
What are his needs or desires?
What or who stands in his way?
What will he do about it?
What happens if he fails? (the stakes must be dire enough to carry an entire novel)
What sacrifices will he have to make?
What heroic qualities need to emerge for him to succeed?
One of the things that I have found very helpful in creating characters for my science fiction novels is to base the characters on people I have known in my life. This will help you understand them and have a better idea of how they would act in various situations.
In Pandemic Dawn Book I, the character Pete is a handyman-type character who is knowledgeable about electronics and mechanical things. He likes to work with his hands and makes a living selling and repairing items for people. He lives on the outskirts of the suburbs with his friend Scott and his mother. Pete is based on my grandfather and Pete's mother on my grandmother. Does that mean they are exactly like them? No, but loosely based on them to give me a good idea of "who" they were and how they would act.