It’s a fine line … Many authors feel the need or obligation to drone on about everything even if it has little or nothing to do with the story … “Mary’s mother’s aunt had long twisted fingernails. Her manicurist only worked on Saturday’s blah, blah, blah,” Others skim over an interesting or important topic too fast. “She was pretty” How do you know when it is too much versus not enough?
My suggestion is to first tell the story. Then, when you go back to read it, ask yourself if you brought your audience into the story. Did you help them visualize the character, the scene, the smells, the sounds? On the other hand, did you add so much detail that you are training your readers to skip to the next paragraph?
As you read or have others read, ask the question … Do I need to elaborate or did I go on too long anywhere? I often hear people say “I wanted to hear more about …” And I never want to hear “I skipped over that part, it was too long and lost me.” It’s not easy to get someone to read your book cover to cover. Their time is valuable, it is your job to entertain them, teach them or take them to another place and time.