Here's some great realistic fiction for tweens:

Beezus and Ramona by Beverly Cleary; illustrated by Tracy Dockray

Every soul a star: a novel by Wendy Mass

The secret language of girls by Frances O'Roark Dowell

Ida B—: and her plans to maximize fun, avoid disaster, and (possibly) save the world by Katherine Hannigan

A corner of the universe by Ann M. Martin

When you reach me by Rebecca Stead

The boy on Cinnamon Street by Phoebe Stone

The mighty Miss Malone by Christopher Paul Curtis

Moon over Manifest by Clare Vanderpool

Otherwise known as Sheila the Great by Judy Blume

Bloomability by Sharon Creech

The lemonade war by Jacqueline Davies

The Mother-Daughter Book Club by Heather Vogel Frederick

One crazy summer by Rita Williams-Garcia

The cupcake club by Sheryl Berk and Carrie Berk