"A writer, I think, is someone who pays attention to the world."
- Susan Sontag
If you are a writer, take notes of the world. Observe things in your life and write / dictate them down for later use.
What does the snow look like on a roof? How does the earth smell in the autumn? How does your body feel after a jog? What does the old coffee machine sound like? What are the sounds like in the street?
Dictating may be easy outdoors - use your cell phone. Then write your dictations down / transcribe them. And then place these into folders. I use Dabblewriter and Scrivener and it is easy to create folders and subfolders there, in the same platform you use for writing your stories, so they are easy to access.
Under cities you may have houses, streets, people, traffic...
Under nature you could have trees, fields, animals, water...
Under people you could have men, women, children, angry, joyful, people of different cultures...
And then, when you write your stories (often when you have written your first draft and start the editing process) you may find great stuff here to insert into your stories. Don't overdo it with details, but add some to give food to your reader's imagination. Hint, and let them imagine the rest, and they will love your story.