I am not much of one for dissecting story structure. I never enjoyed Literature classes for that reason; it seems too bad to pick apart an author's writing until it is hardly recognizable for the story it once was. I don't deny that there is some help to be gained from such dissection; as in the biological world, it is crucial for knowing the interworkings of those living words. But I was never fond of dissections in biology, and I think that has carried over into my reading style as well.
Despite that, however, I do tend to look at stories in two great parts: dialogue and narration. Dialogue is anything inside quotation marks (I lump the protagonist's thoughts into this category, too, since they tend to be in monologue form); narration is, well, everything outside. Both can be hard to write, but the area of dialogue is the one in which writers tend to have the most difficulty. How closely should characters' speech resemble "real life" dialogues? How casual is too casual, how formal too formal? How do we get to the point of a conversation without it sounding abrupt? How do we differentiate between characters' ways of speaking? There are a dozen questions that come up and conflicting answers to meet them.
On the other hand, being idealistic does not mean that written dialogue can be divorced from the way in which people do speak. For instance, unless there is a particular reason intrinsic to the story and the characters, dialogue should not be contraction-free. Neither should characters "over-address" one another, using names more than is appropriate. These points, frequently brought up, are part of the balance that must be found in each author's writing and make up the broad brushstrokes of dialogue. The finer details are much more individualistic and depend a great deal on the characters themselves.