Sun Tzu's 9 situations. is by itself a Powerful GM tool for analyzing character situations. Do not just apply it in combat, approach it socially, and logistically as well. Being able to identify Sun Tzu's 9 situations allows you to simply add on the elements that enhance the risk and challenge of a situation.
(1) Dispersive ground;
(2) facile ground;
(3) contentious ground;
(4) open ground;
(5) ground of intersecting highways;
(6) serious ground;
(7) difficult ground;
(8) hemmed-in ground;
(9) desperate ground.
Ex. Dispersive Ground - this is a situation where the personal weaknesses of the characters can easily overcome them. If you are using disadvantages and understand the motives of your players, Dispersive ground is when they are tempted to give in to a shared weakness.
A party of greedy adventurers might find looting more favorable than a time-sensitive goal that has a much greater pay off. In a situation where the party would rather fight than talk, and where talking is the "smarter" thing to do. The art of war recommends avoiding dispersive ground: or in the case of the PCs, avoid the temptation.
Facile Ground is much like Dispersive ground, except it is in the transition to serious ground (situations where morale and intent is clear). In tenuous conflict, like a difficult melee, there the GM introduces a situations that preys on the discipline of the party. Self-preservation, vanity or pride, and disinclination to think critically create facil ground when the patience of the players wear thin.
Open Ground is when there are too many options, and the NPC opponents also have this many options. Like the dangers noted by Sun Tzu, the first person to move will not be the first to react. These are situations where players who are tempted to make plans and act on unverified information or assumptions.
In much of these situations, the GM is "heaven" or "fate". Since the GM facilitates the situation, he should be able to identify the flow and direction of the challenges through these useful constructs and put his or her finger on point that makes it interesting and engaging.