You can’t describe everything — everything has too much stuff in it. And even if you could describe everything, your readers wouldn’t stand for it; their minds would buckle under the weight of all the stuff there is in the world. So you have to pick and choose. Give your readers not all that there is about something, but two or three things about it to hang their mental image on.
But how are you going to decide what those things are?
Start by thinking about your readers. They’re going to assume that if you’re directing their attention toward something, then it has to be something important, something that they’re either supposed to be using now or saving for later. So don’t let them down by wasting their attention on something that isn’t one of those things.
Stuff that they’re supposed to be using for the scene they’re reading right now would include: a detail that conveys important information about a major character (this one is left-handed; that one is carrying a pistol in a shoulder holster; the other one has one brown eye and one blue eye; and so on); details that help to establish the setting (the floor of the grand hall is polished black marble and the ceiling is painted with a fresco of the apotheosis of King Egbert the Eighteenth); a detail that moves the plot forward (the golden apple has a tag on it saying “for the fairest”; the third red lozenge from the left on the lid of the enameled jewel-box opens the secret compartment.)
Stuff that they’re going to want to save for later might be: the left-handed man’s ebony walking-stick (which he will use for self-defense in a later chapter); the velvet-lined secret compartment in the jewel-box (which will be used in the next chapter to hide the forged identification papers); the polished black marble floor of the grand hall (where the character with the one brown eye and the one blue eye will slip and fall while running to escape the character who’s carrying the pistol in a shoulder holster.)
You’ll note that some of the details up above are doing double duty — they’re establishing something about the “now” of the story and at the same time planting something that will be useful later. Good writing is economical like that.
(And no, I have no idea what the story might be that would involve pistols and walking-sticks and forged papers and an odd-eyed fugitive in a land ruled by the descendants of King Egbert the Eighteenth. But I’ll bet it’s a lively one.)