Besides Trigate, my sci-fantasy setting, I have a few other settings that span across multiple worlds. I'll go into detail how I worked out my system for detailing different types of worlds one may encounter.
The Planar Council is made up of many different parts working together, just like any other government. Its delegates are one of the most important parts, meant to function as representatives for the plane they are from. How are they chosen? What are their responsibilities?
There are two ways that life survives in the world: through rigorous evolution, with mutations causing changes that make survival more likely... or the adaptation of outside sources to secure their place in the world.