When writing for children, there is more to determining audience than subject matter. You must familiarize yourself with age, interest, and educational level.

KNOW YOUR STUFF
When writing non-fiction for adults, you must determine your prospective audience. However, when writing for children, you not only have to consider audience, but age groups as well. Will you focus on kindergarten, early reader, second or third level readers, middle-grade, young adult, high interest/low vocabulary and -- need I go on?
In addition, you have to establish vocabulary level, interest, and comprehension levels. These days, almost any subject can be approached in children’s literature. However, knowing your audience and how to approach the subject matter is absolutely crucial in order to be successful.
So, how do you become educated about a specific audience? Read everything you possibly can in that particular age group, get a feel for word usage, detail, and subject matter. Then, research. There’s simply no way around it. For instance, say you want to write about the great women of World War II. It’s an interesting subject that has plenty of information available, but a very broad theme. Now, what is it specifically you want your audience to know? Pinpoint your focus, and then determine your audience. If it’s kindergarten, your information should be very brief, clear, with a few highpoints this age group can retain, and lots of pictures. With regards to beginning readers, include a bit more information, but keep words and sentences very simple, short, and still use plenty of pictures. Second and third level readers are ready for longer sentences, a little more information, and less pictures. Begin to elaborate with detailed descriptions in middle-grade readers, and feel free to reveal some of the harsh realities and emotional traumas of war. With young-adults, you can take details and truths even further.
Be careful not to confuse audiences. You’ll never pawn off a low-interest/high vocabulary non-fiction, or give away a first reader that consists of one hundred pages. Don’t make light of serious subjects regardless of age group. Yes, children love silliness and humor, but that material doesn’t belong everywhere. When writing about a critical subject for young readers, include an element of childlikeness he can relate to even though difficult issues are conveyed. A child needs hope. A young adult can more handle the blatant certainties of life.
New innovative knowledge provides you the ability to write to numerous age groups, and thus reap revenues from four, maybe five different sources. Nevertheless, in order to reap you must first sow your personal familiarity into each age group.
Research without consideration to age and comprehension level is futile. Your readers must understand the information, and not constantly stumble over unfamiliar words. Though the subject matter may be a bit complex, explain it in simple terms. Even as an adult, when I approach an unfamiliar subject, I don’t want to refer to the five-pound dictionary in my lap.
You can transform non-fiction research into fiction, as well. Susan Campbell Bartoletti’s award winning non-fiction book, “Growing Up in Coal Country,” was a forerunner to her Dear America fiction novel, “A Coal Miner’s Bride: The Diary of Anetka Kaminska.” Both books were designed for middle-graders, but one was non-fiction and one was historical fiction.
Don’t consider research a tedious task, but a door that leads into marvelous adventures, and exciting, unexplored territories in fiction and non-fiction. As Thomas Edison said, “We do not know one-millionth of one percent about anything.”
Opportunities are as endless as knowledge. Take advantage of both. If you know your stuff and your audience, then, my friend, you’re own your way to being known yourself.