Two ideas:
Create a category Habit tracker and populate it with one event for each day of the month that applies to the new habit. So students can keep track together and are not separated into their single track record. You could also write some changing motivational text with each event topic:
Make things more visible and visual by rewarding students with custom badges. I could think of three steps depending on persistence:
And you could extend on these badges by introducing silver and gold lines for repeated participation.