When you write characters in a story, they are more than simple descriptions on a page. They behave, they act, they live and breathe. People have physical attributes; so do the characters in writing. They have senses of taste and smell and touch. Physical or emotional flaws may help shape them. Like the writer, characters think. They have motives, often revealed only through their actions, not their words or even their thoughts.
I might describe Johnny like this:
Johnny is an emotional, overweight ten year-old boy with blue eyes and blonde hair.
Or I might describe Johnny in a different way altogether:
Johnny's ninth birthday party, just a year ago, stuck in his memory like a knife in the gut. The older kids had laughed at him, calling him 'tow-headed fat-boy.' The memory caused tears to well up in his piercing blue eyes. He felt a warm tear slide down his cheek to the corner of his mouth; the salty taste reminded him of what his mother had said: "Those boys knew what they were doing; they were pouring salt on an open wound."
Though the prose in the latter paragraph might be a little 'purple,' it gives more insight into Johnny than a two-dimensional description.
I'd love to read some of the ways other members give life to their characters. Please, if you will, share just a bit here on this blog.