I follow www.teachpianotoday.com
It’s a great source of ideas, and I love this one:
“The Amazing Finger Exercise Cup”
DO watch the video! With the sound on!
I’m going to make some for my own students, and also as class music instruments.
This page gives links to a dozen ideas for fixing technical problems. Make yourself a cup of tea before you start browsing through the links – you could be some time.
http://www.teachpianotoday.com/2015/05/06/17-simple-fixes-for-your-piano-students-the-piano-technique-cheat-sheet/