As mentioned in my homepage, I used to give piano lessons and I did my Diploma with the Trinity College of London (ATCL).
I used to make learning aids for my students back then as they were all relatively young and I even taught a student with special learning needs. The learning aids were effective for teaching and reinforcing simple concepts and are especially useful for the beginner.
In due course, I shall try to replicate the learning aids I used to teach my students with in the past (to teach my daughter). :)