Islands are made from magic dust harvested from various locations throughout the Vale. But not all islands are harvested, some are found. Most of the Islands that special wizards use are often found and they use complicated magic to allow them to be in more than one place at a time.
The internal structure of islands is full of pipes to bring water and transport waste, vaults for storing gems, coins and treats, and housing for the many workers that populate a DragonVale island.
Getting an island to float involves air magic. An island must be stabilized using lightning and earth magic, and temperature-controlled using cold and fire magic. Time magic is used when wizards have special event, this allows the island to be in multiple places at once.
Groups of islands are bound together using complex magic so they don't crash into each other or float away. The stability of a group of islands decreases with each successive island added, so the spells are even more complex, take more time, and cost more money.