Ambrose Bierce's use of foreshadowing in "An Occurrence at Owl Creek Bridge" creates tension and suspense throughout the story. For example, when the protagonist, Peyton Farquhar, notices a ticking sound during his execution, it hints that something unexpected might happen. This foreshadowing contributes to the shocking twist at the end when it is revealed that Farquhar's escape was all a hallucination. Additionally, Bierce's use of flashback in the story adds depth to the narrative by providing insight into Farquhar's character and motivations, ultimately leading to a greater understanding of his desperate actions.