The middle of the story is where most of the scenes take place. One must rememberthat each scene has one or more of three purposes.
The first of the three is to advance the story. Writing a scene that takes the characters nowhere is a wasted effort. There needs to be something within the scene that advances one or more characters toward their goal. The scene could also show a character being diverted from their goal.
The second of the three is to establish the character - Showing who the character is and how they plan to act will give the reader a way to accept or reject the character. If the character acts one way in one scene and another in a second the reader needs a reason for the change in the character's manner. If none is provided the reader will close the book.
The third of the three is to show the setting. Giving the reader the atmosphere in which the characters operate is important. For me this is the hardest part of writing. But this is necessary since showing the setting gives tone and atmosphere and to draw the reader deeper into the story.
Now having seen the three purposes of the scene think of this. To provide one of the purposes is good. Two is better. Three makes the scene really great and keeps the reader turning pages.