In his book The Zen of Creativity: Cultivating Your Artistic Life, John Daido Loori outlines the following exercise - a good one for writers, visual artists, or anyone looking to expand their insight.
Have a friend put five or six small objects that can be held in the palm of your hand into a wastebasket or some other container. The objects should represent different types of tactile surfaces.
Without looking, reach in and take an object from the basket.
Now spend fifteen to twenty minutes exploring the object with your hands, your eyes closed. Feel its every part. Don't try to identify it. As thoughts arise, acknowledge them, let them go, and return to the object.
When finished, return the object to the basket. Repeat this process at another time.
As you continue this practice, you'll come to be able to experience the object directly, without labeling it or identifying what it is.
The exercise can help you develop the ability to just see, just hear, just touch, just smell, just taste - without needing to name the thing. This way of perceiving will allow you to expand how you describe people, scenes and environments in your writing.