Here's a detail that's important: This is Lisa's prompt.
You like that? No? All right, I'll get to the point.
Some details are fun to read, some are enlightening to read, but some are a burden to remember. How can we as authors tell the difference?
When you're reading a mystery or suspense, you're trying to pay attention to little details, little clues, so you won't be in the dark when the bad guy is finally revealed, the mystery solved, the truth uncovered. So when details are given, readers are paying attention, trying to remember. That's when writers need to pick and choose their details so as not to overburden readers or mislead them by seemingly putting undue weight on irrelevant specifics.
Caitlin: I think some of the best advice I ever got was from an agent who rejected me (see, rejections can be helpful!). He said that every line, every word, had to be essential to the story. Look at each word and know that the story would be less if that one word wasn't there. It sounds like too much, but if you think about it, that IS how stories should be told. Now, keep in mind, that the reader might "need" to know that your character has lime green keds in order to understand something about that character, and therefore understand something about the story. But if the reader doesn't need to know that -- CUT!
Karlie: LOL Lisa I guess I inspired this one. Yes, it's a major problem I have - how much detail is too much detail? I always loved stories like The Night Circus by Erin Morgenstern, where detail basically drives the plot. Susanna Kearsley is another wizard when it comes to that. But I started trying too hard and thus wound up with a lot of annoying purple prose. Lately I've decided it's time to bring out the scalpel - the detail is weighing me down instead of lifting me up. Caitlin, you made a really good point, too!
Dan: I have less experience with reading mysteries, but in sci-fi and fantasy, it's all about the details. You get some aspect of interstellar space travel wrong, and the readers will be all over you. With fantasy, it's a balancing act. You want to provide enough details to make the world compelling and convincing, but not so many that the readers start skipping ahead. But I'm with Caitlin when it comes to details in editing: if it's not critical to the plot or setting or character, it has to go.