As a book editor, I often see writers use too many words–more words than are needed to create the moment or make the point.
Every piece of writing needs white space. This gives the reader a chance to pause and let the ideas resonate.
Wordiness can consist of:
Repeating. Saying the same thing in two different ways. Saying something one way, then saying it a different way. Expressing the same idea more than once. Saying the same old thing over and over. Being repetitious.
There are…that. Often you can lose those flabby words. “There are three components that this system relies on.” Better as: “This system relies on three components.”
Overexplaining. Not stopping at the end of a sentence, but going on with more words. I could have made that, “Not stopping at the end of a sentence.”
Editorializing. Commenting on the action (in fiction) right before or right after it happens. You don’t need showing plus telling–just one or the other. Example: “In the chaos of that day’s scene, they did not notice her secrete the tiny metal blade from the surgical table. Ironically, her luck had not run out.” The last sentence is editorializing. Let the reader have those thoughts.
Stage direction. Overexplaining unimportant actions. “She walked across the room and reached out her left hand to turn on the light.” Better as: “She turned on the overhead light.”
What is wrong with extra words?
#1 If you qualify and overexplain even small moments, the reader does not feel trusted.
#2 Wordiness is tiring to read. Over the course of a book the words slow the reader’s pursuit of the story or information and make them NOT want to turn the page.