Hemingway had the ability to look at his surroundings and describe in detail what he saw.
Ask yourself the question: What did you see?
Describe in words the things you are seeing. Put words to what you see.
While Hemingway was a writer, it is a great practice for painters to look at things and put words to what you see. Put these thoughts along with pictures in your journals.
Look at the scene and decide what you want to emphasize.