It's been a long week. Therefore, today I'm taking a break from my usual effort to be upbeat.
Nothing kills momentum in a book better than a great big chunk of description. Start describing the scenery in an epic fantasy, and I groan and grit my teeth until something happens. Pause the narration to catalogue a character's physical features and I sigh impatiently. Contrive a book of descriptive passages with little dialogue or action to break it up, and I lose interest.
Description is necessary in stories, but there is such a thing as too much. In books, it's rarely about what you do once that makes something badly-written. Generally, it's repetition that turns a decent book into a bad read.
The worst descriptive mistake, though, is when the narration is repeatedly interrupted to describe what a character is wearing.
There are certainly times when we need to know what someone is wearing. If her clothes have been transformed, or if he's trying to make a statement with his outfit, or if it's a character quirk that so-and-so wears funny t-shirts, I want to know that. I'm talking about taking a paragraph or two, every time the character changes clothes, to describe them down to the label.
Not only do I not care, it feels creepy. It feels like I'm listening in on an obscene phone call. Whether a character is wearing practical shoes is appropriate to the narrative. Establishing that someone wears t-shirts and jeans or business casual all the time may be important. Describing every wardrobe change is piddling along instead of telling the dang story.
I've heard several different takes on describing physical appearance, as well, and I think this can be overdone. Some readers like to have a perfect picture in their minds of what characters look like, but I prefer a blank canvas I can project an image onto based on a couple of reference points. I prefer if only a couple of the most noticeable features are given in a narrative, and that's the approach I've heard advocated most often.
Reading is an act of imagination. I like to use my own, instead of authors forcing theirs into my head.