You will be able to understand everything I write here, but you can look at all this as the extensions to my functions model if you exchange content element to function in the text. Elements of content can be anything from story elements to things like the GM asking a player to roll the dice.
A roleplaying session is made up of people introducing content to the game. Usually that means that the GM introduces many-many prepared content and all players (inclusively the GM) adlib some content while playing.
Let's have a look at this act of content generating. The adventure writing is somewhat complex, so its discussion will be postponed. Now it is time for the adlibbed content.
Basically in a classic session there are two types of adlibbed content: the player's character decisions and the GMs reactions to the player's decisions.
How is a player's decesion (an adlibbed content element) generated? First, the player looks at the content element just introduced into the game, then looks at the prepared character. The relation of these two content elements will generate the decision. (Of course the generation needs the creativity of a human being.)
How is a GM's decision (an adlibbed content element) generated? First, the GM looks at the instructions of the adventure (wich is a prepared content element) and/or the situation the PCs are in and then looks at the just introduced player's decision (wich is an adlibbed content element). The relation of these content elements generate the decision. (The human creativity is needed here, too.)
What's common in these content element generations?
Every generated content element is generated by two other content elements. Note, that content elements don't have to be part of the active content wich is known by all the players. Content elements can be part of the thoughts of only one player.
Then why is it practically important that a new content element is generated by two other content elements if any player can have any content in their heads? Because it is always quicker to generate new contents from existing ones. If you have to wait for your ideas, that means that you risk that maybe nothing will come to your mind in the session.
The more content you can generate the better. You don't have to introduce every possibly generated content into the game if it would harm, but the more the possibility, the better you can choose.
Fruitful Content
So you generate content by looking two or more conent elements and then generate a new one based upon their constellation. But content elements differ in how fruitful they are. For example if you wait for your ideas, that can be very random. If you consistently look for content elements to generate new content, that's better than to wait for an idea from nowhere. But the best are those content elements wich automatically generate more content because of their nature.
For example the personality of a character is a content like that. It makes a pair with every situation the character gets into. But even better if you can describe a character as short as you can. For example if an NPC is all about 'I endure everything and everyone should pity me.', that means you can follow this only one sentence without knowing the thorough personality of a character. It not only gives birth to character decisions, but generates probable situations or memories that the character likely has. You don't have to flesh that out, because it gets fleshed out automatically while playing.
If you consider to use more fruitful content elements, you can spare many work when writing an adventure.
Introducing Contents is Communication
The history of roleplaying makes us (the players) difficult to talk about preferences and if we do often miscommunicate or just say vague things that don't mean enough for each other. (For example: 'We want excitment.' or 'We want a good story.' mean nothing to the GM if players say things like these.)
But the content elements introduced by players mean business. Of course even this type of communication is distorted somewhat, but not as much as the out of game communication. For example if the player at character developement when - has freely to choose wich skills to raise - raises fencing, that means that the player is awaiting or is preparing for fencing itself.
Note, that these are different content elements: the raise of the skill and the use of the skill and the skill itself are three different things.
You, as a GM, can react to the introduced contents. For example if the player raises a value of the character, you should introduce trials of the very value into the adventure. It is just trivial to introduce battle if there are fighters among the characters.
But this also works on other types of content elements. If for example a character is lazy, you can play on it by inventing a situation where lazyness is a problem OR lazyness is the solution.
If we step one more step, we can say, that it is even logical to assume that it works with adlibbed contents, too. If a player attacks on spot an enemy without consideration, you can introduce more fights even in the same session. That gives even shy players some achievement, because the story bends as they want it.
Teaching the Players
The GM has to 'teach' the players communicate using the content elements, if there is a traditional GM role in the game. Unless the game has to teach the players the communication. What does that mean?
That means two main things:
1. The players may assume that they 'have to' do some decisions. That there are better decisions and there are worse decisions. For example some player may argue that in a fantasy setting it is wise to have some skill in physical combat, wich causes them to raise the combat skills while they don't want at all to fight, they're just afraid that they will meet combat trials. All the players have to know all their possibilities.
2. The other important thing is information. If a player doesn't know some important information, than the player can't make real decisions. The game becomes random. It is important that every player gets to know every content wich has been introduced to the game.