Just reviewing my notes about structure written when I was halfway through my third novel (as yet unpublished). Aristotle... good material.
1. Single Place
Aristotle called this Unity of Place: he recommended that no play should cover more than one physical space; and definitely should not get into gimmicks like compressing geography or representing more than one space on the stage.
2. Single Action, Objective, Challenge
Aristotle called this Unity of Action: he recommended that the story (play) have one main action, with few or no subplots. Can you imagine a primetime hourlong with only one plot? Samuel Beckett's play, Waiting for Godot, comes to mind - two men, Vladimir and Estragon, waiting for Godot by a tree along a deserted country road. A few sitcoms have attempted it (i.e., Mad About You in which Paul and Jamie wait by the bedroom door for the baby to fall asleep).
3. Brief Time (a.k.a. 'time lock')
Finally, Aristotle suggested - you guessed it, in his Unity of Time - that no play should cover events representing more than 24 hours of time. Hmmm... so a season of 24 actually represents the Aristotelian ideal, right? Each episode follows Jack through exactly one hour of his challenging existence. That's a time lock. Yet, at the risk of nitpicking, while he follows one overarching action, he is all over the world trying to achieve it. My guess is that Aristotle wouldn't judge 24 too harshly. The structure works.
Hemingway's For Whom The Bell Tolls is another example of the essential power of Aristotle's Classical Unities:
1. Strategically important BRIDGE in war-torn Spain 2. Jordan must DESTROY the bridge 3. He has 3 days in which to achieve his objective... 72 hours
Apply that to just about any story and you see the pattern. There IS method ...! How many times must we rediscover what we know?