What were the three main elements of "An Occurrence at Owl Creek Bridge"?

If you're
after certain structural elements instead of simple partitions of the story, consider these
-

Use of the third person limited point of view
-  The story takes place from the viewpoint and understanding of
theonly.  Most of what happens is only in his mind, as the reader learns at the end of the
story.

Use of flashback and
virtual reality - Although the reader is not aware of it at first, the
"events" in the story don't happen in chronological order but are subjectively
selected (between real and imaginary ones) by the character of Farquhar.

Use of dramaticand a surprise ending
- Up until the very end of the story, the reader "lives" the
events of Farquhar's fantastic escape. Just as he "makes it," though, the reader
realizes it has all been an illusion as Farquhar's neck snaps under the tension of the
rope.