Characters do not live by structure alone. Background information and personal attributes are needed to turn these avatars of dramatic purpose into living, breathing, human beings (or whatever). 

In addition, the physical qualities of your characters will have a tremendous impact on how your reader/audience receives them.

How does each character move, what does it do with its hands? Does it have a nervous tick? A lisp? A permanent grin? And what about its stature, its weight, the color of its hair (if any). Is it pretty, handsome, pretty handsome? All of these can apply to men or women equally well but with different effect.

Take a moment for each character and picture it in your mind. Write down all you see. Then put it in motion and see how it glides, stumbles, slumps, or bolts. Note its motions and note them well. What you work out here can turn a paper person into cool character.

Excerpted from
Dramatica Story Development Software