Oh...my first fanfic/story, the start of it… pure dialogue in committee style, discussing how to better Harry’s falling marks (because he’d been spending all his time in the owlery writing love letters to his muggle girl.) I certainly wouldn’t write it that way anymore! I’ve grown to figure out way better ways to have done it. I also wrote in PRESENT TENSE, which… wasn’t great either.
One trick I learned ages ago for details, don’t describe it ALL. Instead, draw focus to one specific detail, ie, a tear in the green lamp shade, and it gives the illusion of depth without pages of detailed description.