One thing that worked for me as well - and it built trust with the parents and showed the kids I was trying to be invested in their improvement... is I would send a quick email summary to the parents after each practice.
My summary would focus on what we covered - the highs/lows and maybe 1-2 areas where each boy individually should work on during the next week. Nothing major - it took 20 minutes to type, but I'm telling you - the parents enjoyed it and it shows you care about them and helping them to improve.
__________________
|