The first convention that Avi used in both books that I read was the cliffhanger. Cliffhangers leave the reader not knowing what will happen next. At this point in the story you don't know want is going to be done about the barn. You have to read the next chapter to find out. Avi also uses first person point of view.
Point of view is who tells the story.
First person is when the story is told through the main character's point of view. This is the narration technique that is used for The Barn. In the seven months since I'd seen him last him, he appeared to have grown about a foot. How I envied his size and strength, his shovel wide face and those hands as tough as horn. This is a description of Ben's older brother, Harrison, through Ben's eyes.