|Make a chart or table to keep track of how often you practice your violin.
While I recommend a journal of some sort to keep track of teaching points, I also recommend some sort of visible reward to show consistency in practice. Check off your day's practice on the chart as you put your violin away. You get a feeling of accomplishment when you can see that you haven't missed a day's practice for two, three or four weeks. Or maybe keep track of how many minutes you practice and reward yourself when you reach a numerical goal!
And praise your student when he achieves those goals of two or three week without a miss! Or even better, two or three weeks without having to be reminded to practice!