When it comes to setting a scene, or describing any environment, it’s practically a given you need to know the ins and outs of the area. And like with most things, I take this very literally and go too over the top with this like the sixteen-legged freak I am.
If you know have the foggiest idea about what kind of environment your world resides in, then a good place to start is working out that first is a good place to start. Now this doesn’t need to be anything detailed the vaguest idea of the weather is good enough for now. Brainstorming this will help building the environment.
Once this is done you can start to put scenes to places. What places do certain scenes need to be in? What kind of weather do you want to occur? Is there a real-life city or architectural equivalent in real life? It’s around this stage I start to gather a portfolio of pictures that I believe best suits my environments. This way, whenever I’m stuck for words on a particular setting I can refer back to it, for inspiration.
At this point it’s a good idea to start adding detail to your environments. A good way to do this is by working through the senses, (sight, sound, smell, taste, touch) adding as more information as possible to each bit. What colours are there? Is it a dry environment? What kind of materials are in the environment? So, on and so forth until the setting is built.