'Mr Francis entered the room. There was a piece of paper on the floor...'

The 'paper on the floor' in any other situation seems pretty boring & unimportant, but in narrative, it actually has some significance. I think it's because it actually will have something to do with the plot of the book, because if it had nothing to do with anything in the story, it would have been taken away in the editing of the story. For example, the piece of paper on the floor may be a clue to help figure out a murder, or something along those lines.