We used this site: http://uxmastery.com/sketchnoting-101-how-to-create-awesome-visual-notes/
To understand why some of these things pop out and make you remember.
I now realize looking back that math is a very difficult subject to try sketch-noting especially the section on radical expressions. I gave students the option to try sketch noting on paper or use the iPad app Notability to help them.
Here is a student example:
It turned out pretty good, they got the general concept of putting things in boxes. It was difficult to draw pictures and include thought bubbles, but for right now it is a start and will want to do this with a more user-friendly topic.
Here are some other examples: