Clearly, now, a SHOW and TELL topic.
Concrete descriptions are much more effective in conveying a scene then an abstracted description or a conclusion. As the Honorable Judge John Hodgeman would say "Specificity is the soul of narrative." Imagine a room that smells weird. This is a conclusion. The players may smell dust, sweat, and that sweet sweet smell of rotting death. They may think to themselves "this rooms smells weird." That's the conclusion the players are drawing from the DM's description. We WANT the players to draw those conclusions rather than feeding them the conclusion directly. Instead of the text indicating that the room smells weird the text should indicate that the room smells of dust, sweat, and that sweet stench of decay. A room that has scary lights? Again, conclusion. What makes it scary? Green, faint, flickering, darting about? That's a more effective description. It SHOWS why the lights are scary rather than just TELLING it is scary.
Voice in the Machine, by Will Doyle, is part two of an D&D adventure path.
"The Salvage Market is a dirt-floored warehouse built from scorched wood planks scavenged from the Mournland. The room reeks of dust, sweat, and oil. In here, the town’s brokers do business from behind armored counters."
Note the conclusion here: "In here the town's brokers do business from behind armored counters." This is a conclusion. We don't get a sense of the brokers, or their armored counters. We're just told that's what happens here. A better description would have left the player with the impression that the towns brokers do business behind armoured counters.
A separate example in the adventure. The party travels through a fog bank straight out of Fury road. This is the text provided: " Leaving Salvation, you’re soon swallowed by the fogbanks that encircle the ruined nation of Cyre. Strange shadows flit through the mist, distorted voices bellow from afar, and a supernatural chill reaches deep inside you. Beyond this border, a twilit landscape of blasted battlefields stretches as far as the eye can see."
Note again the "strange shadows" and "distorted voices." (As well as the sin of telling you what you think by referencing a supernatural chill running through you.) [Move this to the correct section?] Contrast this with the description of the fogbank from the first adventure in the series: " As you approach it, the fog churns into ominous shapes: screaming faces, collapsing buildings, and outstretched hands. Explosions flash within the gloom, but no sounds are heard." Much more visceral. It's not telling you what you think, that you feel a chill or that the sights are shadowy. Instead it is showing us what is going on and then the Players gets to make the conclusion that the sights are shadowy.
voice in the machine dmsguid fogbanks and its from here that business is conducted from behind ... text