Take a notebook to a public place. Observe someone for a moment. Make a note of their appearance, their mannerisms, and, if you are able to hear, some of their conversation. Now imagine some extra details by creating a list of questions that you will answer about them:
- what is their home like?
- who lives there with them?
- if they have a job, what is it?
- what is their secret?
- etc etc
Generate a list of questions. Then answer them.
Now write a scene featuring this character (make sure you give them a name).
Write for at least 15 minutes, without pausing to edit or censor. Let it flow, see where it takes you.
If you want to share your writing in the comments section, it would be great to see how you get on.