Describe the world in 3 dimensions. What is above? What is below? What is around? Then go into further descriptive detail where necessary I.e entering a city for the first time, describe it using the 5 senses such as does it smell clean or gritty, are the buildings uniform and sturdy or haphazard and flimsy, are the streets even and kind to walk on or sodden and trying to snatch your boot from your foot etc.

Using our everyday perceptive experience to describe a made up world, helps to immediately wrap your head around the complex fantasy space and helps to incite memories of similar more mundane experiences making it much easier to imagine. It also does a lot to help with the mood of a setting.