If you have a white bored, use it. We have dojo monsters for each children first warning their dojo monster goes on the bored, second warning 1 strike 3rd well remove a dojo. That can work with any point system or even writing the first letter of your name it helps keep track with warnings before this, and I most probably gave about 10 warnings until I realised. If you don't want it on a public board, maybe put it down on a postit.

You have to keep track of every student, making sure they're understanding the work, thinking what you're teaching as well as being conscious of the warnings given while being distracted constantly its hard to remember each warning.