Building Campaign Settings

[DamnedIrishman]

Hello.

I am in the habit of having ideas and never writing them down, so I decided that I would start doing so. With regards to D&D, many of the ideas I have are regarding what I feel is wrong with fantasy settings and how I would create one that I thought was better. So, I've vaguely started in the direction of writing up a campaign setting from scratch.

This is not really a dedicated project so much as something I can add to now and again in my free time. However, if I'm going to do something I'd like to do it right and thus I thought I would ask for people's advice on building worlds. The Giant's New World series was informative, but I feel there could be so much more.

For some reason, I started with cosmology. At this stage, most of what I have are ideas which I've had that could fit together. My setting is envisaged as primarily taking place on one as-yet-unnamed world. This world is the fifth planet in a nine-planet solar system. One of the dominant factors in my ideas is the law-chaos spectrum. The sun in my system is also a representation of Chaos - burning, changing, creating. Beyond the system, the void of space is the ultimate Law - empty, still, silent. The position of the planets in the system is representative of their tendency towards law or chaos - the hot inner worlds being generally chaotic, the cold outer worlds being generally lawful.
Travel between worlds is possible in one of two ways: through space (difficult) or through special gates which acts as focuses that allow teleportation magic to work over the vast distances required. I thought a nice little rule would be that the alignment of the planets would have an impact on whether and how well the gates worked, but I'm more interesting in flavour than mechanics. Needless to say, interplanetary travel is rare.

The various races originated on the different worlds, and have migrated to greater and lesser extents between the planets. Planetary origin relates to the races' general alignment. Elves in my setting are accustomed to icy wastes due to their lawful natures, whereas halflings are far more resistant to heat as they come from worlds closer to the sun.

For the sake of practicality, I was thinking a good place to start would be to create one city-state and surrounding region rather than worrying about designing an entire world (or entire worlds, for that matter). Would you agree?
The idea I've had is a culture dominated by lizardfolk (a lawful race), living in a very organised city and reliant on slave labour. The city is circular, and prominent landmarks act in a way similar to stone circles - the city can be used as a giant calendar by it's rulers. The lizardfolk are obsessed with geometry and astronomy, but otherwise are fairly standard Mesoamerican themed.

Thoughts, advice and suggestions more than welcome.

[DracoDei]

Since replies seem to be slow in coming, let me throw out an old idea I had... note that this MIGHT only apply to SOME, or maybe even ONE of the worlds in the larger setting you are describing:

The Wereworld Facet (and I DO suggest you keep the fixed alignments)

[Yora]

It is a start, but as presented, they are just some details.

I think to really get an interesting setting going, you need... let's say: "a vision".

It's not how the world is, but what it is about.

Exploring a huge and completely crazy city with weired characters at every corner, which is choke full with portals that lead your adventure into another new fantastic landscape every game session. - Planescape.
A huge invasion by undead and demons that turns the world into ruin and several hostile races have to stand together against a terrible and ancient evil, while still wanting (and trying) to beat the crap out of each other. - Warcraft 3
Being an action hero in a world of magical monsters and steam punk and having crazy fight on speeding trains and impossibly high tower roofs. - Eberron
Struggling through thick and ancient forests to uncover the magical and fantastic mysteries of the great fey lords and demi-god dragons and helping the young humanity to advance to a level equal or even greater to the great dwarven and elven empires who rule the small pockets of civilization inside the massive wilderness. - My own creation.

What special thing do the PCs do? I think that's the really important issue to tackle.