One of the things that Emma Dryden and I discussed when she critiqued my manuscript was the fact that I should read middle grade novels with 11 year-old protagonists. I knew that, but then she asked me who I would read.
Big
blank
brain.
The only author that I could think of was Bruce Coville. His magic shop books feature 12 year-old protagonists who are new to using magic so they’re pretty on the mark but I really needed to read more than one author.
Fortunately, I’m on a list for children’s writers so I sent out an e-mail. I also posted on Facebook. These generous souls responded and I soon had a list to take to my local library.
Before you start a new project, especially if it is a kind of writing you’ve never done before or don’t do often, read. Read new books for the same audience. And if you can’t come up with enough examples on your own, ask librarians. Ask teachers. Ask other writers. Fellow book lovers will point you in the right direction.
Here is the list my friends helped me put together:
Adam Gidwitz’ :
A Tale Dark and Grimm
In a Glass Grimly
Gary Schmidt:
What Came from the Stars
Joni Sensel:
The Farwalker’s Quest
The Time Keeper’s Moon
Skeleton’s Knife
Anne Ursu:
Breadcrumbs
Melissa Wiley:
The Prairie Thief
Patricia Wrede:
(Enchanted Chronicles series)
Dealing with Dragons
Searching for Dragons
Calling on Dragons
Talking with Dragons
(Frontier Magic Series)
The Thirteenth Child
Across the Great Barrier
The Far West
–SueBE
One Writer's Journey 
That’s great advice! And it sounds like you’ve got a wonderful list there with plenty of good material.
Another great one is Phyllis Reynolds Naylor, who wrote the acclaimed SHILOH series. The first book was written in the 90s, but the feel of it is timeless.