One thing I had them do was a character sketch. Sometimes the character was from a book we were reading, others were character types I gave them and they had to write a description. I do not claim to be an expert at anything but my own little world, but I have found a few ways to get fourteen through seventeen year olds to write. I’ve incorporated the same exercises for myself, so I know they work for adults as well.
Pick a character you want to develop but are having trouble getting hold of:
Start by giving him or her a name.
Decide on his age.
Hair color. (Include facial hair)
Skin type and color.
What he wears.
What he carries.
His voice and manner of speaking.
Does he have pets? Do animals even like him?
Does he live alone? Where does he live?
Is he healthy?
Is he a good person or an evil one?
Does he like people or does he shun their society?
How does he travel?
Tom the Magician -all right it’s not very creative, but he’s got a name! None of this is written in stone. A better name can be given to him later.
Age: He is ancient.
Hair color: His hair is pure white and he has a long white beard.
Eyes: His eyes are piercing blue.
Skin type and color: His skin is pale and like parchment.
Clothing: He wears a black woolen robe that is in tatters.
What he carries: He carries a gnarled staff.
Voice: His voice is a deep baritone. He tends to stutter.
Does he have pets: He has an old Greyhound and an Irish Wolfhound who share his cave.
Does he have family: He has no family.
Where does he live: In a cave in the mountains.
Health: He doesn’t take care of himself and tends to cough a lot.
Good or Evil: He’s a good man, but not a terribly good magician. He has a bad memory and makes mistakes in his spells.
How does he travel: He doesn’t travel because he’s made himself so unpopular with his botched spells that he doesn’t dare go far from home.
Habits: having been alone so long, he talks to himself.
Once you have gotten the sketchy details you can flesh him out and think about where he is, what he's doing, where he's going, who he's with. Do a basic Who, What, When, Why, How like a journalist, only you don't use journalistic jargon. Read through your character sketch and make changes until you are satisfied with it. This process can be done for any character you create.
One thing I always keep in mind, my characters have an existence of their own. They make their own decisions, go their own way, and do what they want. Remain flexible, today’s villain may be tomorrow’s hero!