It is a definite challenge. Fantasy has the problem in particular because the worlds aren't often our own or there are specific elements that are different. You want people to be able to see the world in their mind but with the other things of fantasy and science fiction, there might need to be more details.

As a writer umm. I don't do much description. It's something I need to work on in my rewrites and edits because first drafts don't have much. I do exposition sentences that get long and confusing but not much about setting. Even in the long, 180,000 fantasy novel first draft, there isn't much in the way of description over the setting or details to how things work. Have to divide it into two novels and find ways to describe things without going too far.

Good questions. I shall have to think about that in particular with the witch/detective series since it's similar to our world but different with the clear view of magic plus the non-human characters.