Hello Frankie,
Getting to know and understand story characters is an essential step in story planning. I suggest you first think carefully about the physical appearance of the character you visualize as filling the role in the story. Just as film actors are cast who fit the director's vision of a proposed character, authors should find a good photo example of every important story character. The easiest way to do this is to review character photos found on stockphoto websites.
Then, create a full personal profile of each character that describes in detail the background and motivation of the character in the story.
A character profile should be as detailed as possible, even if most of the details never appear in the story, so that story characters stay "in character" at all times. Also include characteristic speech patterns that serve to identify characters by their dialogue and reduces the use of dialogue tags. The protagonist should also have a personal prejudice/phobia identified that affects the character's behaviour at the start of the story, which is changed or overcome by the story's end to show how story events have affected the hero. Here is an example from my book
Story Craft"The WIFE: Melissa Susan Anderson ADDRESS: 6 Wellgrove Court
TELEPHONE: 555-6724 AGE: 42 HEIGHT: 5'6" WEIGHT: 121
MARRIED: 16 years CHILDREN None
MEASUREMENTS: 35-29-36 EYES:Brown HAIR:Brown
EDUCATION: Master of Arts from City University
EMPLOYMENT: Various part time jobs while attending school. Two years at Vanity Gallery of Fine Art after graduation. Volunteer work for the City Art Museum.
ORGANIZATIONS: Democratic Organization for Womens Advancement; Womens Club of America; Wellgrove Golf and Country Club; Willow Creek Home for Abandoned Children.
SPORTS: Likes golf, but only shoots in low 90' s. Hates horseback riding. Plays cards with friends
TALENT/ SKILLS: Fair portrait artist. Good, but thin, singing voice. Melissa is a well spoken, upper class married woman. Married stockbroker Jack Anderson after six month engagement, when she was 26 and he was 38. Met husband while volunteer at university alumni reunion. Melissa is an attractive, intelligent woman with excellent taste and grooming. Because of her husband's wealth, athletic exuberance and outspoken attitude, she has become reserved and retiring in public. Her friends and social contacts respect her opinions and listen when she chooses to speak. Her friends know very little of her background and Melissa does not discuss her past prior to entering university. Her support of the Willow Creek Home for Abandoned Children is not known by her husband or friends. She took her first lover two days after her thirty-sixth birthday party because her husband drove a female guest home and didn't return for two days. She met her present lover six months ago at the City Art Museum exhibition for new artists. Three weeks later she showed up on his doorstep with a moving van and announced she had rented him an apartment and it was time to move.
"Character descriptions permit a writer to know and understand each character, and consequently keep their persona and actions consistent throughout the story. As a story is written, additional character attributes or information should be included in the character description. It's a good idea to include a dialogue and voice profile with examples. Print each description on a separate page, and keep them close as writing progresses to ensure everyone stays in character at all times."
I don't think using personal characteristics of real people found on Facebook is a good idea unless a story is biographical and about an actual person who is on the Facebook website.
JMO
Tony