Table Plan: I Can Feel The Cosmos

I understand this Table Plan is very, VERY belated!  I'm usually very poignant and punctual with posting these things on Monday.  However, this day has been a bit crazy, so let's discuss something just as crazy, the Planes!

How can one create an effective Planar System and Cosmology that doesn't feel bland or cliched?  This is a toughie for me.  Basically, its because I love the Great Wheel from D&D.  I love Planescape.  In fact, I have reconciled Eberron so it can work with Planescape.  I will admit my bias here.  However, I have created my own cosmology for both my main campaign setting, and one for my Window setting (my main is grand and epic, my Window is is generic, but works).  In my main, to be vague enough so not to reveal too much about it yet, the Planes are based on grades on how distant one gets from physical reality.  Eventually, you get to a place where the plane is a blank canvas and literally every thought that passes through your head, no matter how minor, suddenly manifests.  So, if you imagine a Pit Fiend doing a Rocky Horror Medley in fishnets, sure enough, one appears.

So, the first thing you need is a concept.  Planescape was based around Idealism, and how different Ideals are represented by the planes.  Real World religious cosmologies are based on concepts of Suffering/Punishment, with the Heavens being realms of rest and relaxation, and Hell being a place where you push boulders up a mountain for the next eon.  Fourth Edition has a dualism of material versus mental/spiritual, with the Astral Sea and the Elemental Chaos.  My setting is based on the separation of Physical Reality and Mental Reality, which leads to that one famous question from that one famous rock song.

Remember, this gives you not your cosmology, but your starting point.  The Mountain of Celestia and the Infinite Layers of the Abyss are not the only places.  If you have an established Bestiary, think about where your Extraplanar beings (angels, demons, etc.) come from, they need homeworlds.  Maybe your world's elves come from a foreign realm to, like the Feywild of Fourth Edition D&D?  If you do not have an established Bestiary, look to religion, mysticism, and such for inspiration and ideas.

Also, keep in mind that this is not a physical world you are making, the planes tend to be crazy and infinite.  Weird Gravity like on the D&D plane of Bytopia, frictionless surfaces, the mind being able to shape and bend matter without effort, all can happen.  While you should restrain yourself while making a World, with the Planes, go buck wild!  Go Mount Meru or Divine Comedy or Lovecraftian!  Nothing is too unbelievable with the planes, everything is permitted!  How awesome is that?

Last but not least, don't let your low number of planes make you think your cosmology is not good, or don't feel compelled to make a very varied cosmology, with billions of demiplanes.  Work to what would be great for you.  If only a few planes is your cup of tea, do that.  Likewise, if you love making varied and crazy worlds, go for a Planescapeish cosmology.  After all, here, finally, only your imagination limits you.