A needless scene is one that serves no purpose where the story stands at that moment. It might have in draft one or draft two, but right now with the final draft, the scene does not add to the plot at all. You need to access every scene to see if it is crucial or needless. Then you need to eliminate it.
Test #1 – Does the scene contribute to the plot?
The couple is sitting in the park talking. What purpose does it serve? Does what they say reveal more of the plot or the characters themselves? Look at the scene in the big picture to the entire plot. Does it contribute to it? Is it crucial? Some scenes are good to give history that is important. Others help to give the reader insight to the characters, but you don’t want to put in scenes just to make the book larger. Even a well written scene could be entirely needless. What does it contribute to your overall story?
Test #2 – If the scene was cut, would the plot suffer?
If you took that scene in the park out, would the plot hurt from it? It might be a cool scene, but what does it add to the overall story? You can always remove it and save it in another document. You might find it works better in another part of the story or could be used in a completely different story you write later.
Needless scenes are basically fillers. Many authors put them in to make their book longer. Your book doesn’t have to be over a hundred thousand words to be a great novel. I’ve read many that were only twenty-five thousand and many over a hundred thousand. Size does not dictate quality. In fact, many agents and publishers will not even look at a book that hits the 100,000 word mark. I read where one bestselling author was told to cut twenty-five thousand words from his manuscript before they would start the editing process. Wow! That was a lot and took him a long time. But it created a better story.
Read over your manuscript. Pinpoint the needless scenes and eliminate them.