This is merely a collection of tips I have accumulated after having been in this fandom for six years; do not take every word as law, but I hope this comes across as helpful. (: I don't mean to bash on other works, and this may come across as a bit sarcastic, but if you can bear with that it's all great.
A queen lays on her side, her swollen belly going up and down in heavy pants as she strains to push another kit out.
"Push, Peppermintcrazy, push!" the medicine cat urged, and with a final gasp a slippery bundle passes through. The medicine cat quickly nips the sac open and puts the new kit beside the rest of its siblings.
"They're so beautiful," Peppermintcrazy's mate crooned. "How about Shinykit because she is shiny, and Diamondkit because she was born right next to a diamond?"
"Perfect," Peppermintcrazy purred, rubbing her nose against the new litter -
"This concludes the first chapter! It is very pleasant," Nightwing declares, and as soon as she said so the projector screen crashed upwards with a mighty crash, causing the audience to shriek. The black she-cat shakes her head disappointingly at the projector but continues on. "I mean, I love the detail of birth and all - "
Freakishlyoldface blinks.
" - buuut I really don't understand how this has anything to do with anything? Like they're born, it's all good. Same with kit scenes. I don't understand, unless they find like a dead corpse outside or something significant who cares that they woke up, played around, and explored the camp?"
"Well, it's important to know how they're named because of the prophecy about Diamondkit!" Violetfoot says defensively. "And about how much she loves her kits."
"I guess that makes sense. But no one cares. Try to make it a bit original?" She ignores Violetfoot's offended gasp and presses the remote, moving on to the next slide of the powerpoint. "The exposition is generally at the beginning of the story and introduces the setting, characters, and other elements necessary for understanding the story. Even if you did do that, it is a bit cliche and it doesn't matter if you skip that chapter. Like no one cares about their birth and how much pain their mother had to go through."
"I care," Freakishlyoldface says mournfully. "I remember when I was a little tot, and mother, Freakishlyyoungface ... "
"Unless something very special happens at their birth. Maybe she gives birth after running away or having a prophecy being delivered. Maybe the medicine cat dies while the kits come for some weird reason," Nightwing announces, raising her voice.
" ... and what happened back in my day ... "
"Hey. Hey Freakish."
" ... and I said, 'well, you look like a prune more than I do when I was born ... "
"That is disgusting. I'm kicking him out next time. This closes our first meeting of Warrior Cat Writing Tips. Nightwing, out." She struts down the stage, basking in the lukewarm applause of the audience.