I would want to compare and contrast these two excellent stories in relation to their plot by talking about the way in which both of them contain a surprise ending, or an ending that shocks us and makes us sit up and think. In both of these stories, this ending takes us by surprise because of the way in which subtle foreshadowing is used to point towards the ending.
For example, in "How to Tell a True War Story," the ending actually is an admission that the whole story is a lie and is a figment of the speaker's imagination. Concepts such as "truth" and "fiction" are therefore deliberately played with and abused as Tim O'Brien seeks to answer the question that he gives to this story as a title. Consider the following quote:
Beginning to end, you tell her, it's all mde up. Every goddamn detail--the mountains and the river and especially that poor dumb baby buffalo. None of it happened. None of it.
We definitely do not expect to read a story and then to be told at the end of it that it was all made up, yet this is crucial to the story's theme concerning the difficulties of expressing one defining truth when it comes to war and what happens in it.
Similarly, in "A Rose for Emily," the ending includes the discovery of what precisely happened to Miss Emily Grierson's beau and why it was that he disappeared so suddenly. The discovery of his corpse and the final paragraph makes for a somewhat chilling ending to this tale:
Then we noticed that in the second pillow was the indentation of a head. One of us lifted something from it, and leaning forward, that faint and invisible dust dry and acrid in the nostrils, we saw a long strand of iron-grey hair.
Just as in "How to Tell a True War Story," the ending of "A Rose for Emily" therefore shocks us, but for different reasons. We understand that not only did Miss Emily kill the man that she loved, but that she did it to gain possession of him and to sleep next to him in the same bed as him every single night. In both stories the crucial information is therefore delayed until the end.