John D. MacDonald made this statement in an essay. "The writer must provide the materials with which the reader will construct bright pictures in his head." When I wrote this several years ago, and re-reading this again, I realized how true the statement was.
When I thought about what this meant I realized those words meant the sights, sounds, taste, smell and touch of things. Describing those give the reader a way to associate with the story and build a picture of what the world you've created is all about. Think of writing about a house. Sure you can describe it as a rectangular box but then add the little details and you can make the house any house you wish. Let's give it a try.
The house next door is a Victorian. This does bring a hazy picture to the reader. But add something like this. The "Painted Lady" next door wore her coat of pale lavender with purple touches. Brings the house in clearer. Perhaps this house is different. The purple shutters on the Victorian house next door hung like limp fingers. Gives a different picture.
In other inspirations we'll look at the other senses. Sight is one used often by writers but the use is more like "She saw a tall man. Or she saw three children. Or he saw a car." I could go on forever but you get the picture. Without the little picture the reader will glaze over what the characters see and forget. He saw a sleek red convertible and envy filled his heart. She saw broad shoulders and wondered how his shirt remained intact. Of the three children, one caught her eye. The little girl's yellow curls resembled a dandelion making her wish to run her hand across the child's head.
Hopefully you get the picture. But using sight beyond the mundane helps the reader form a bright picture in his head.
So with luck as you write, you will add those touches of paint to your prose and the reader will suddenly be in the world you have created.