Some ideas: You could start growing some more grass maybe. You could make a landscape and/or a house if you want; you could also make a water fountain somewhere for decoration. Also, you could try using some glass (maybe white stained glass?) in some places if you want, like a glass floor could look pretty interesting; you could make a big glass greenhouse over your crop farms. You could make a spawn room, buildings for your farms, or some small decorations perhaps. You could incorporate different block types (stone bricks, concrete, etc.) around your island if you'd like. You could also create visible paths in the flooring going to various places
