I absolutely love Joyce Myer. Here's a quote from her.
A #2 pencil and a dream can take you anywhere.
-Joyce A. Myer
Write wherever you are. Whether you are in a park, on a boat or at the golf course. Stop for a moment and absorb the scene. Do not try to make sense of the piece. Simply write notes, using key words to describe what you see. Later, you will recall details from the same scene to invigorate your imagination.
In a park scene for instance, you might note the following. Trees. Mostly oaks. Scattered pines. Box hedges at the far side. Children kicking soccer balls. Screams. Birds chirping. Crowded parking lot. First day of Fall.
You get the point. Scenery gives us the effect of the actual motif.
You might want to extend this exercise. For example, what kind of birds are in the park? What is the state bird...the state insect? What types of trees are indigent to your area?
Is there a pond nearby? Tell me about the ducks. Are children trying to catch them? Let's explore the smell of leaves, freshly cut grass. Let me feel moisture from the pond or hear an occasional duck flapping its wings.