While the experts seem to disagree on how long it takes to establish a new habit, all agree that the more you do something, the greater chance it will become a habit. With the beginning of the school year, I find myself trying to establish new behaviors. Chains is a free website/app (works on desktop and mobile devices) that allows you to visually track your progress. While I am working on healthy life habits (my longest chain is only 5 days), I bet you could use it to track classroom activities/behaviors. You can create several chains for a variety of events and can skip days when the event doesn’t occur.
Below is a screen shot from their site. You can read the complete blog post here from ProfHacker.