This was years before No Man's Sky and similar games so I didn't have a lot to go on, though one big inspiration was Spore. The island generator is something that has followed me through many projects and languages and I would probably extend it to more generic terrain generation, but for the game I had in mind I wanted to start with just the island.
Below you can play around with the galaxy generator (the stars have temperatures modelled on reality!). Because of the way these stars are generated (with a location as input), you need to hit "generate" after adjusting the parameters. Drag and scroll/pinch to rotate and zoom respectively.