Creating a skyland is a group level activity which should be done before play. I will present a few example skylands, and the group could just use one, but it is always better to design one to fit the group.
Each skyland has at least one Region. A Region is a homogeneous chunk of mountains which has torn loose from the earth and floated up into the sky. Now "mountain" is a relative term - these are low mountains, like in the eastern US, rather than real mountains like in the Alps or Andes. They would be at most about 1.6 to 1.8 kilometers high - that is the limit before they go skyward. That's a little over a mile for the metric-impaired. This pulls up a lot of attached not-mountain too - valleys, plateaus, and foothills, all relatively fertile. The Regions would have an area somewhere between Luxembourg (Rhode Island) and Belgium (Massachusetts) in size. Aside from the initial region, the skyland is comprised of any captured regions. Each region has a different physical look and feel, and definite borders - although over time, attached regions integrate into one another somewhat.
So regions are thus the atomic unit of the skyland, and each region has to be defined in creation. Each region should have a City, Mineral, Animal, and Vegetable resources, and Manufactured Goods. I am going to make things simple, and give each region a Primary, a Secondary, and a Tertiary good, and carry that nomenclature over to each of the resources as well. I think this makes the effective combination of goods and resources unique and definitive for each region. The Manufactured Goods being produced in the City, while the resources are produced from the hinterlands of the region.
Each region would also have a unique culture, which would also be defined by its characteristics. I will be using the StarCluster 3 method of creating a culture via the medium of a fictional "typical" person of this culture. This can be "drilled down" with increasing variation by size from this norm to define any sub region or other internal division, to the point that any given individual can have no particular relation to the fictional gestalt. I'm also thinking of defining a regional art as well.
This method means that the weakness of any given skyland is that it is made up of disparate parts, and the larger the assemblage of regions, the greater the danger of balkanization and ultimately fragmentation.