Well, this has to be a good start. I’m actually interested enough to do some research on writing for middle grade children (that’s the 8 to 12 age group).
The following information was taken from Ask Laura at Write4Kids and was written by Laura Backes:
1. Middle grade novels contain about 12-15 chapters, with about six to eight book pages per chapter. This translates to up to 10 manuscript pages. This is just a general guideline; your story might require more chapters, but will probably fall within this range.
2. The traditional middle grade audience is ages 8-12. There is also now an upper middle grade age bracket of 10-14. The main thing that differentiates a middle grade novel from a young adult book is that the protagonist is 10-14 years old (most are around 12) and so are dealing with problems and concerns of a preteen, as opposed to a high school student. Middle grade characters are wrapped up in themselves, their friends and family. Young adult characters also think about these things, but in the context of how they fit into the larger world. Young adult characters are stepping across the threshold to adulthood, whereas middle grade characters are learning how to be adolescents.
3. Subplots are a hallmark of middle grade novels, and are what set them apart from simpler chapter books for ages 7-10.
4. Most publishers accept a query letter along with one or two chapters. Send for publishers’ guidelines to be sure.
And this was a comment made about talking animals, which I’m not sure if I’ll have or not but it’s worth knowing:
Talking animals aren’t completely taboo, it’s just that most writers don’t do them very well. What’s important is that your animals have completely developed, unique personalities and characteristics. You need to develop these characters just as carefully as if you were creating human characters. Too many writers use their animal characters as stereotypes, thinking kids will be immediately drawn to them just because they’re animals.
Everything your animals say and do should be a logical extension of their individual personalities. And give your readers some surprises. For example, a rabbit might not be cute and cuddly; he may be absentminded, selfish, or cunning. I suggest you read some previously published “talking animal” books to get a sense of what I’m talking about. William Steig and Kevin Henkes are two good picture book writers. Also, Charlotte’s Web by E.B. White (a middle grade novel) is an excellent course on how to create unique animals characters.