Simplify the supplies. I can’t stress this enough. With your child’s teachers’ permission, purchase multi-functional items. Less stuff to manage means fewer items to forget for each class. Think unfussy and streamlined, which is always better for a student with ADHD.
One idea that works well for students who like to keep each subject in a separate binder is an accordion binder that comes with a loose-leaf section for taking notes AND a 7-pocket accordion file for housing homework, tests, etc. The accordion even fits composition notebooks, an academic planner, and small books. This eliminates the need to carry all these supplies separately. And since it is available in 10 different colors, she can easily color-code all your child’s subjects.
If your child's has a block schedule (different classes depending on the day), an accordion folder will keep everything she needs in one place.