I've been long planning a low fantasy campaign whose meta goal is to help me better world-build and set scenes for my players. The meat of the campaign will focus around tightly built set pieces, where most of my previous games have been world trotting sandbox adventures. The plot is that the party are a crew of specialists employed by an ambitious, but good-hearted count or other minor nobility, handling odd but sensitive jobs for him, while he is busy CK2'ing his way to the top.
Occasionally work will take them out of the home city, with such adventures as find a giant that is living on a rivals lands, and make him leave, with possible outcomes being they fight the giant, convince it to return to it's distant homeland, or even convince it to move onto their lord's lands. Another would be to investigate the disappearance of a key spy in another city, find out if he's been compromised, rescue him if possible or destroy any information extracted from him if he was found.
But much of the campaign I expect to take place within the home city, where a sense of place can be built, and from there a grounded point of view. Once the players are immersed, you can make it clear how unusual the bits of magic in the world truly are. That giant is not something anyone can find by walking up a mountain, and it's met with fear and distrust by everyone around it, because they are unusual, the nearest clan of giants live hundreds of miles away, and the average person never travels more then 20 miles away in a lifetime.
Elves and bugbears may be real, but they are the subject of myth more then politic. People speak of maegi in hushed tones, to not draw the misfortune that follows such poor people upon themselves. If the players start thinking of the magic as the mysterious and unusual, it will give it more impact when they encounter it.