Everyone begins walking around the room.
After 30 seconds change one thing about your walk. Maybe you start walking faster, or swinging your arms.
How does this new walk feel? Who would walk like this?
Now change another aspect of your walk. How does a character that walks like this feel? Why does he/she walk like this?
Grab a sheet of paper and draw what your character looks like. Give him/her a name and a personality!