So I've got an idea that I want to run with for an RPG.  But I've never gotten very far in such an endevor before, and what I need some help with is how to go about explaining things like theme, and storytelling in my RPG (I plan to have sections detailing both). I haven't seen any articles that would help an RPG writer with such a thing, so if anyone could give me some advice or links on the subject it would be much appreciated.  I need to be able to explain such things as how theme applies to games, and how to go about GMing in my own words, but I do need some help to get started.
Just to give you a basic idea of what the GM/storytelling aspect of my RPG is going to be based on, pretty much its going to be centered around the Hero's Journey.

There are a variety of ways you could do it. Many of the games designed here have approached that problem by embedding the story structure in the procedures of play. Check out the articles section here for some of the background on that.

But here's a useful first question: In your RPG, who decides the theme and when?

Does the GM decide it pre-game? Do the players (and/or the GM) decide it as play progresses?

-Matt

well, I tend to think of setting theme/mood and such are primarily the GM's job, as in most cases that's how games are ran (in my experience).  However in this game there's going to be times when the psyches of the characters are going to start affecting reality (this game draws from mythology heavily, but I also want stories like Alice in Wonderland where the world the character is exploring is a reflection of their own psyche to be an important source of inspiration).  Because of this I think in this game there will be times when the players will actually need to start taking part in the "GM's job". 
Anyhow I'll have to take a look at the articles section again, I haven't visited it in a while.

I'm not certain what the overall gameplay mechanic of the game is, but generally I imbed my plot in the scenario.  Whether it be a character, a location, or some powerful artifact, I try to lead my players with hints.  When they don't follow the hints, they end up in more danger than I'd originally intended to put them in, and have to feel their way around.

It's kind of like blind man's bluff.  If you put the turning points of your story in places where the players are sure to find them, then it's challenging without being aimless and meandering.  Video Game RPG's have that shortcoming in spades.  I can't recall how many times I've explored some dungeon for hours before finding the key or candle, or person I need to talk to in order to further the story.

AsuraDemon wrote:
well, I tend to think of setting theme/mood and such are primarily the GM's job, as in most cases that's how games are ran (in my experience).

Well, honestly it's been almost a year since I've played a game, everyone around here is really into LARP, and I've gotten really bored with it, and the few people I knew whom played D&D don't have time anymore. I'm trying to find people whom would be interested in table top and have the time, but haven't had much luck.  But in the past the GM has always been the one to set the theme/mood pretty much, and in some games I've played that just amounts to the standard "we're heroes hunting down villains" or "we're villains terrorizing the populace". 
In the case of WOD LARP, well the themes were political intrigue and that sort of thing in most of them, things which I could never get into, at least not the way the were dealt with in vampire LARP.  As for mood, well it was somewhat dark, and perhaps a bit paranoid.
What I've experienced in the past there should be some elements of in my game, but they shouldn't be that important.  For example there should be some hack n' slash, but that really shouldn't be the point of the game, there should be a darker element to it, but equally, maybe even more so, there should be an element of wonder, and the potential for political intrigue is there if players want to pursue it, but it's not what the game generally focuses on.
What I do want the game to focus on is

A: The power of imagination, and the power of the psyche
B:The possibility (which is a reality in this game) that what we see around us is not the only reality. 
C: The Hero's Journey

To some extent the GM is going to give the players a reason to go from one encounter to another, this is part of the hero's journey, it starts off with a call to adventure, and the GM will probably give the players that call to adventure.
But I do think that maybe there should be times along the way where the GM and players interact in the role of storytelling. 

Here's a possible scenario that I just thought of.
Lets say a character is in the dream world (a realm where imagination, and state of mind really does define reality), and his state of mind has not been so good, he's been having trouble at work, and has been really concerned about losing his job.  So the reality of the dream world start to react to his fears about losing his job (along with some other subconscious fears), allowing them to manifest as some sort of monster which represents them. 

Now should it be the GM that controls the character's fears, and even determines how they manifest?
Or should this be a time in which the player would be better off running the scene, and determining what sort of form their fears take and how they behave?
I'm not too sure.

I guess it would help if I posted some more information about my game as well, it's still an evolving concept at this time, but if anything I enjoy bouncing ideas back and forth online.
Right now I'm calling it Somnium Viator, but I'm really certain what to call it.  Also the game is focusing on Heroic humans as the race, staple fantasy races such as elves and dwarves are in the game, but not PC friendly (they play very different roles, and are mysterious not truly knowable beings, think of them more as living archetypes).  I will eventually detail other "races" but all are human to a large degree, for example dragons that became human, and demigods, but they are not as primary to the game as Heroic mortals.

Somnium Viator is an RPG in which players take on the role of humans that come from a world very much like our own.  They had ordinary jobs, families, all the same dreams, and fears that ordinary humans do.  But Somnium Viator is not about living an alternate life as a mundane human, it is about that mundane human becoming something more.  In the world of Somnium Viator the mundane reality in which these characters once lived, is but one of many.  The universe is made up of an infinite number of other realities, full of magic and wonder, from the realms of Arcadia and Midgard, to the Dream world.  These realities call out to the Somnium Viator, also called Dream Walkers or Heroic mortals destined to become a wounded universe's heroes.  The Weave, the mutable and magical aspect of reality empowers these humans, allowing them to transcend the boundaries that ordinary humans have, making them capable of gaining inhuman strength and intelligence, and even shaping the world with the power of their imagination, but the power of the Weave comes with a risk, it can also drive a man insane, and can cause the Heroic mortal’s fears, and hates to be made manifest.

Hello asura,

The game you describe reminds me of a few familiar movies and books. The dream aspect, alternate reality and heroic journey are common in many works and you could definitely gain the attention of many. The Cell with Jennifer Lopez is an excellent interpretation of the fantastic mind, journey and danger within. Dreamscape is an older film that is very simple and not so dark. "Talisman", a book by Stephen King and Peter Straub would be something for you to read as it describes how the characters are altered versions in two realities. Here are some reviews on Amazon.comhttp://www.amazon.com/Talisman-Stephen-King/dp/0345444884.

Torg is a game by West End Games where the earth experiences shifts in reality and parts of the world exhibit certain properties or axioms. Not so much like your game, but it has the idea that people are altered by the region and can alter reality. I like the game, but it just didn't get a hold of the masses.

This game would be a great way for the players to collaborate on the setting, theme and story for each character and the group. Your game could be comprised of a base mundane world (our own) where the characters are normal humans who are acquainted in some way. They may be completely average or be extraordinary (financial genius, great athlete, brilliant scientist, etc.) Each player determines his or her character's dream realm (preferably an earth timeline and location, fantasy setting, science fiction setting, etc.) Each character has an alterego in their dream realm, which is defined in detail by the player. Each players then develops a horror that is an amalgamation of his or her nightmares, paranoias, phobias and dark secrets. One player gets to play the horror and can pop-up in any dream realm with an appropriate form, abilities and motivations. Each session in a dream realm is partly governed by the source character and the horror. The other characters are there to support the main character in his or her quest. Supporting characters enter the realm with their original essences, but take on different forms and functions. Supporting characters could be a faithful servant, powerful steed, intelligent weapon, damsel in distress, eccentric wizard, etc. The goal of the characters is to vanquish each personal horror and support the other characters. In the mundane world, characters can only communicate to each other in the form of ideas (gain and loss, faith, fame, fortune, death, love, hate). So, the characters can talk to each other about their problems only in terms of the mundane world where they have very little power. The dream realms are an interpretation where the characters can affect their lives. For all practical purposes, the characters are oblivious to their dream realms, yet the events that take place affect the mundane world directly.

I think developing parallels in each realm will give more substance to the story and make the goals more than just "kill the bad guys". They become moral issues along with fantastic action.

Troy

btw What is your name?

The idea of having realms which are a entirely the manifestations of an individual's psyche is one I like, they could exist as sort of sub-realms of the Dream World.  I also like the idea of players collaborating on the setting theme and story (though of course along with the GM). 
I've decided I defianately I want to include a place on the character sheets for fears, desires, vices and virtues as well, and for players to decide some ways in which those things might manifest themselves while on the dream world or other realms.

The alter ego you are talking about sounds similar to a Doppelganger, which I have been working on a write up for.  I'll post the in progress write up for the Doppelganger here, along with one for the elf which isn't as far along.  For each creature I'm detailing what sort of role they can play in the Hero's Journey and such.  I still have to research the Hero's Journey a lot more, so this may have some flaws.
I'm thinking now that I might have doppelgangers look identical to the character they are a double of if they manifest in the mundane world, but like some sort of horrific monster which represents the darkest aspects of the character if they manifest in the dream world.

Doppelgangers

Sometimes a person’s dark side can manifest itself, and take on an independent life of its own.  Doppelgangers are manifestations of the dark side of a person’s psyche.  Though they look like the person whose psyche they were born from, some of them have subtle differences in appearance.  Though doppelgangers are manifestations of the psyche’s darker elements in general, each one has one particular aspect of the psyche that is predominant.  Inflicting a fatal wound on a doppelganger will only put the creature out of commission temporarily it will show itself again, maybe in days, maybe in years, unless the character confronts the darker aspect of their psyche that the doppelganger is primarily a manifestation of.
Doppelgangers are born in the dream world, but they are capable of entering other realms through the character’s shadow or reflection, and also of pulling the character into the dream world through the character’s shadow or reflection.

Doppelgangers in Hero’s Journey

Doppelgangers are most obviously suited to play the roll of "The Dragon", however doppelgangers could also (and most likely in addition to being The Dragon) be the Herald, of the Hero’s Journey.  As Doppelganger’s almost always try to force a character into adventure regardless of whether they are worthy or ready (indeed since Doppelgangers want a character to fail if anything they will try to get the character to embark on their journey before they are ready), and they are also very much malicious towards the character and any one whom is allied with them they are poorly suited for other roles such as Threshold Guardian, or Mentor. 

Doppelgangers as Heralds
A doppelganger could play the role of Herald. Its entrance into a character’s life could very well disturb things enough that the character (and their adventuring group) could be forced into an adventure to pursue the creature.  The doppelganger could pull the character into its own world, or it could simply show up and start interfering with the character’s ordinary life, by pretending to be them.  Unlike many other Heralds Doppelgangers always try to force the Hero into the Journey, rather than trying to convince them in less forceful ways.

Doppelgangers as the Dragon
The role that Doppelgangers are best suited for is that of the Dragon.  They are malicious creatures whom are the embodiment of everything negative about the character they are the double of.  In order to destroy the Doppelganger the Hero must confront them, and what they represent. 

Elves

Elves also called álfar are creatures of Nordic mythology, and mostly seen on the realms in which the Nordic mythos predominates.  Elves are the fey children of the Norse gods.  Like other fey these beings have extremely strong ties to some feature in nature, such as a grove of trees or a stream, this feature is called the Elf’s fetter which they inhabit most of the time, almost as if it were their physical body.  Elves live along side other spirits in the area, and they are usually very protective of the natural world and the spirits which animate it, particularly the ones which are the animistic spirits of their fetter.  If an elf's fetter is destroyed or drastically enough altered they cannot physically manifest.  Elves like other spirits are truly immortal beings.
Elves appear as extremely beautiful graceful humans with distinctively pointed ears, their skin is usually pale, and their hair usually blonde and their eyes usually blue or amber colored, they radiate an aura of sunlight.

Elves and the Hero’s Journey

Elves as “The Dragon”
Elves can just as easily be antagonists, as helpful beings.  Their reasons for being antagonistic are as little understood as their reasons for doing anything else.  Elves can be cruel pranksters, bringers of bad dreams, and just outright dangerous.  Elves have been known to occasionally embark on what are called Wild Hunts, in which they abduct humans, and transform them into wild beasts, after which they proceed to hunt them down as such. 
Abducted humans are not always hunted down and killed however they may be taken to live among the elves as well, usually put under a powerful enchantment.  Elves can represent what a Hero fears about the unfathomable or unknown, and also fear of a loved one being taken away.  Elves (and other fey) sometimes take away things that the Hero at first thinks they want to get rid of, leading to family members that the Hero doesn’t particularly like or want anything to do with to being taken, only later to have the Hero realize that they didn’t really appreciate what they had while it was there.  The hero must confront and defeat the elf in order to regain what was lost.
Elves can also serve as a villain that forces the Hero to confront what they fear about nature, or the unpredictable and illogical.