Most of the writers I know (me included) work on their stories everywhere they go. Taking experiences and pieces of character to be used later.
As an exercise:
Take a look at the three photos I snapped in the park today and create a story. What’s happening? Who are the two men in the uniforms? What are they doing there? What about the cab driver? What’s his story? What do the men ask him to do? What happens next?
Take a few minutes to write your version of the events and post your story below.