I have valiantly tried to follow in Debbie's footsteps in letter writing. I have about 480 students and so it's hard to get a note to each one each semester (especially when they move in and out as much as my students do) but I have persevered as much as possible. Writing adds about 15 minutes to my days, sometimes more, but the return for my efforts has been amazing! It really, REALLY makes you look for the good in every student and praise even the smallest of strides that they make. The great thing is that if you send home a letter early on in the year about what good things they're doing, a call or note home to parents later talking about their not-so-great behavior is proceeded by a good note. Parents have a good notion of who you are in their head and they're more likely to help you than if they were just to get a negative note about what their student is doing wrong. Students really treasure their notes and for weeks after getting a letter are noticeably more confident and excited when they come to music class.
This adds a lot of extra work, and it's sometimes hard to find something about EACH student to praise, but I tell you that this has helped me to know my students better and connect better with EACH student. To me, it's worth the extra work.