From the 10,000 word post:
"Having produced a setting with these characteristics, as DM you must perceive that your principle goal will be to provide CLARITY. Having plopped your players in your setting, it is less important that you provide options for your players to follow, than that you begin to create their suspension of disbelief by completely and accurately describing what it is they see and understand about the place they find themselves."
How is this done? With great freakin' difficulty.
Understand first: I am not saying in the above quote that providing options for your players isn't important. It is very important. What I am saying is that their suspension of disbelief is MORE important - otherwise the options you provide will be evidently contrived, and will completely fail to achieve the running you want.
What is suspension of disbelief? It is a formula by which a presenter enables the audience to accept fantastic or non-realistic elements because they want to, and not because those elements are necessarily "real." An audience will accept magic. An audience will accept imaginary worlds. An audience will accept a wide variety of things, such as foreigners who speak English, or the convenience of objects that happen to be present when the heroes need them, or explosions in space. An audience will accept these things because an audience does not care that these things are impossible - they are interesting, and that is all that matters.
As a presenter, it is your responsibility to be interesting; it is your responsibility to give the audience what they want - even if they don't know what they want; and it is your responsibility not to fuck with the formula. How do I mean? The formula states the audience will accept falsehood and fakery if it is presented consistently, and if it retains all the elements of drama - that is to say, if the villains are dangerous and the heroes have an even chance of winning.
No matter what anyone tells you, all narrative comes down to Dudley Do-Right vs. Snidely Whiplash.
Oh, we can get sophisticated. Snidely can be presented as Hannibal Lecter; he can have the vagaries of Mrs. Robinson, or the cartoonishness of the Joker, or even the genial ignorance of George W. Bush; but Snidely exists as someone that seems insurmountable. If he is to be pulled down, then he must be pulled down FAIR and SQUARE ... meaning from a narrative point of view, by someone using the best means they have available in the cleverest way possible.
If Dudley can destroy Snidely with a snap of his finger, the drama is lost, and so is the audience's acceptance. If Dudley has been having trouble for all this time, then suddenly finds a way to get rid of Snidely with a snap of his finger, that's just as bad. Snidely can only be destroyed by Dudley one way: Dudley has to suffer every step of the way, and when he takes Snidely down, it has to be a near miss thing. Dudley can have superpowers, but if those powers are more than enough (even by a little bit), the audience won't buy the formula and you've goofed.
In D&D, the whole world is Snidely Whiplash. The party is just an ordinary Dudley Do-Right, doing its best to survive against all this impossibility. Oh, we can be sophisticated. Dudley doesn't have to "do right" ... he can do a lot of wrong. He can be almost as evil as Snidely. That doesn't matter - because it isn't how Dudley acts that's important. It is how Snidely treats him. Or, how your world treats your players. No matter what your players do, the world is ALWAYS against them, and they are ALWAYS against the world. They may find friends; they may find allies; but no matter how many friends or allies they find, Snidely will always have more ... and to win, the party will have to do it by the skin of their teeth.
Your job, as DM, is to see that it happens ... just ... that ... way.
How? Here is where I talk about completely and accurately explaining your world. There is a reason why this villain-hero formula has worked since the dawn of time. We all, you and I, every person you meet, lives a Dudley vs. Snidely existence. It isn't as grotesque as Batman vs. Gotham. It is down on the ground and ordinary, yet it is tinged with discontent and dissatisfaction at every turn. As a DM, you want to begin presenting your world as an ordinary thing. Describe the bar. Describe the river next to the party's camp. Describe the trees and the fields and the distant mountains. Most of all, concentrate on those things that most annoy a party, and mix those in with things that don't. There is a beautiful glade, but there are flies. Here is a beautiful girl, but she's rude. Here is the promise of a treasure, but there are monsters and traps. The party has the treasure now, but there are bandits. The bandits are dead now, but they have brothers. The party has returned to town with wealth, but there are taxes. They've paid their taxes, but the townspeople resent the party's wealth. And so on, and so forth.
You must try to place yourself where your party is, and you must wonder to yourself, what isn't quite right with this situation? I don't mean that the townspeople should all appear and try to seize the party's treasure. I mean that they should present their unhappiness in small ways. Spitting when the party passes. Refusing to serve them drinks. Having the guard harrass the party over where the party has tied their horses. Pestering the party. Making them feel unwelcome. Getting things stirred up.
As I say, ordinary. Not the world burning to the ground, but the same little things that every player associates with the real world as annoying. We all go to jobs. We all deal with people. We know what we like and what we don't like. We know just how much we'll take before we snap. So be Snidely, and push them until they snap.
This is a 'clarity' your party will understand. Trust me when I say you won't win them over with long descriptions of what the king wants or what the nobles have done lately. The party won't care about far off wars, or the color of the barwench's eyes. There is a natural disbelief they possess, and if you present a world that has no drama in it, all you will have from your players is disbelief. Yes, its a nice castle. Yes, its a nice town. Oh, what a nice army. Right, the road goes somewhere. So what. You know that it all sounds awfully boring. These are the 'options' I spoke about above. Your players don't need another flat painting of your world. They need someone to step in and push the party around a bit. Make 'em feel less at home. You know, like we all feel, most of the time.
They will believe in the world when the world you run feels like the world they know. This is what your players expect of you.