Chapter One — The Voice of the Marble
______Jayda entered her room in an enormous fury. Accidentally knocking over Kep’s food dish, she watched a colossal amount of dog chow streak like fireworks. Brown nuggets lay at her feet, and some had landed all the way across the room. She was even sure a few pieces slipped under the lid of an old wooden trunk to her side. In bitter annoyance, Jayda praised herself in the genius of placing her dog’s food dish so close to the door.
______Just then, Kep came shooting out from under the bed. Reaching Jayda, he barked and stared up with pitiful eyes, succeeding as any dog with a master’s degree in manipulation to make his owner feel positively terrible—only about what? Jayda had yet to know.
______The room was a disaster, and would have rated at least a five on the Richter’s scale had the damage been done by an earthquake. A dishevelled mix of laundry, smelly boots, along with anything Jayda had picked over while bored or procrastinating lay in bunches. Carpet was visible—a good sign. The room had been much, much worse.
______But, as Jayda dropped her school bag and walked to her bed, not the tragic state of her room, or even the unexplained guilt she felt for her dog could get her mind off what was bothering her: Dr. Coug.
Answer on How do you find this intro?
It's a good start. I can tell you've worked hard on this passage.
You seem like you want criticism, though, so I'll give you all my best opinions.
If I were you, I would switch to 1st person. Your voice is very unique and recognizable--it adds to Jayda's character, and it's too sassy for a proper 3rd person narrorator.
Keep in mind that this intro may be the most important part of your story. A lot of people only read the first page before they get bored. You spend half of it describing dog food and the other half describing a messy room. Your description is nice, but I suggest you start with a more dramatic scene that conveys excitement or fear or anger or some kind of intense emotion. The only thing this makes me feel is mild annoyance.
At the end of the passage, it looks like you're about to either paraphrase what happened with her and Dr. Coug or have a flashback. Both are looked down on by professional writers. Paraphrasing goes against that old aphorism: "show, don't tell." Flashbacks are jarring, and they detract from this scene you've already spent four paragraphs building up. If what happened with Dr. Coug was so bothering, than open your book with that scene.
Also, your word choice is a little too fancy. "Colossal?" Is it truly colossal? Because, when I think of a colossal amount of dog food, I imagine a bunch of those big Costco bags of dog food dumping onto the floor, covering the room an inch deep. I know you're exaggerating--hyperbole, and all that--but it doesn't make your description any better. It's just annoying.
I like your comparison to "fireworks." But a colossal amount of anything couldn't move like fireworks--it'd move in more of a wave, I'd think.
The second sentence of your second paragraph is quite awkward. "...suceeding as any dog with a master's degree in manipulation to make..." I think what you're trying to say is that it was as if Kep had a master's degree in manipulation. But what it sounds like you're saying is that, as any dog who had master's degrees in manipulation could, Kep suceeded to make her feel terrible (implying that many dogs have master degrees?)
It's kind of a mixed metaphor anyway. First you're making up a fake master's degree, then you're attributing it to a dog.
Anyway. It's "Richter scale," not "Richter's scale." And I don't like that comparison either. An earthquake knocks things over. An earthquake doesn't make "laundry" and "smelly boots" and clutter appear everywhere. You can have a room that looks like it's been through an earthquake but is still clean.
A lot of writers have this problem, where they use 1) unnecessarily hyperbolic words and 2) unnecessary (and unfitting) comparisons. Longer words are not always better. Ironically, sometimes you can draw attention to something better by understating it. Look through some Vonnegut or Hemmingway. You don't have to use incredibly intricate descriptions to write a striking paragraph.
This probably seems pretty nitpicky, but don't get me wrong--I like it. I like Jayda's personality, and the entriguing chapter title. I would love to read the rest. Please post the rest, sometime.
I hope this helps, and I hope I haven't offended. Good luck, and don't give up!