Progress:

Joe is not progressing at the rate that I believe he is capable.  Lately he seems distracted during lessons and I suspect he is not practicing enough to benefit fully from lessons.  He has a lot of potential and I am confident he can advance well beyond where he is now.

Suggestions:

It's best to practice at least 5 times per week, 30 minutes a day. He should practice exercises slowly at first, then build speed.  During lesson time, Joe should focus on the task/s at hand and eliminate distractions (i.e. Having his phone nearby).