The first thing to consider when designing your island is its geography and climate as well as the overall size of the island. Islands may have sandy beaches, coastal cliffs, sea stacks, coral reefs, sea caves, and other coastal elements. Internally, islands will feature terrain elements that reflect their climate or biome. They may feature volcanoes, forests, lakes, secluded pools, or waterfalls. They may be prone to mists, fogs, or storms. They may range in size from incredibly small, to near continent sizes.

Consider if the island is connected to the mainland in some form, either physically or by some form of consistent transportation. This includes ferries, landing pads, underground tunnels, bridge systems, or transient land bridges. The island may be a tidal island, only truly separated from the mainland during a hightide but connected during low tides by a sandbar or tidal flats.

Consider what structures, buildings or settlements exist on the island. There may be working fishing towns, or only ruins. There may be cliffside pathways, or perilous bridges that span mountain peaks. Islands may be home to remote research stations, hidden temples, disease colonies, or prisons. They may host a lighthouse or dock system.

Islands are highly defensible locations, and may be sites of castles, forts, or watchtowers.

Islands may have their own culture and history apart from a mainland, especially if they are in remote locations separated by a vast expanse of ocean. The next thing to consider is the culture and history of your island. Who lives there, and what kind of society have they built?

Another key consideration is the plant and animal life on your island. What kinds of trees, flowers, and other plants can be found there? Are there any rare or exotic species? What about wildlife? Are there predators to watch out for, or friendly creatures that can be domesticated? The flora and fauna of your island can provide interesting opportunities for exploration and discovery. In more fantastical worlds, islands may be home to extinct species, behemoths & leviathans, or other fictional creatures and fictional plants.