1) Become a substitute: That’s right, consider becoming a substitute teacher. You will get more material than you know what to do with.
2) Volunteer in school: Volunteer to teach a creative writing class to kids and use the time to observe them.
3) Keep your eyes open: I don’t want you hanging around in parks, watching kids, because that could get you in trouble, but hey, children hangout in perfectly acceptable public places so pay attention to how they look and act.
4) Keep your ears engaged: Listen to speech patterns, dialogue, general vocabulary, but…
5) Don’t add slang into your book and don’t add all the “likes” you hear. Kids talk like this in real life, “So, like, we went out, and he said, like, I hate you!” That doesn’t work in a book, even though it may be authentic.
6) Stroll down memory lane. Do you have momentos from when you were that age? Diaries? Letters you wrote relatives? Photos? Trying to remember your own worldview at that age will help your writing. Circumstances and technology might change, but fundamental human emotions tend to be the same.
7) Have kids yourself? Don’t tell them I said this, but spy on them with their friends when you can. It’s an opportunity for some major information gathering.
8) Keep an observation journal: See anything interesting? Hear anything? Write it down. Don’t just leave it to memory. These details are invaluable, whether it’s for this book or two books down the road.
9) Read: Yes, read middle-grade books like crazy. These authors got it right, and you can learn a lot from paying attention to good kid lit.
10) This last one is not a “way,” but “advice”: Don’t aim for a “normal character.” While you want the voice to be authentic and sound like a real kid, a “bigger than life” character is often more interesting to read and love. Don’t be afraid to make him or her unique!