When you’re in a public place such as a coffeehouse or library, look around and choose a person to write about. Don’t worry about coming up with any sort of plot; simply write about them in any way you wish. Write about the elderly man at home searching for his keys before he could leave the house, the young boy wanting desperately to hold his father’s hand, the store clerk curling her hair before leaving for work, the mother waiting impatiently for her coffee, her thoughts swirling eddies. Describe them in any way you want. Create personalities for them. Shape their lives. Give them a beloved turtle. Give them a spouse with bone cancer. Give them a profound fear of the ocean. Give them a lucky sock. Make them interesting. You might find yourself creating characters that you’ll use later in your stories or novels.
Attached to (my characters) are what I’ve borrowed, perhaps unconsciously, bit by bit, of persons I have seen or noticed or remembered in the flesh – a cast of countenance here, a manner of walking there, that jumps to the visualizing mind when a story is under way.