We have successfully given lessons online and our students and parents really like it. We use a blend of online software such as Zoom, Skype and Google Hangouts. In addition, students use Google Docs as a means of working on material and sharing it.
We also utilize a technology called SmartMusic which can be rewarding way to practice music because the student is able to realize immediate feedback in regards to whether they have learned their pitches and rhythms accurately. Of course, the art is ultimately so much more than these things, but they are essential to becoming an excellent musician. Proper use of dynamics, characterization, language, and musicality of the work are also equally important and those need to be coached with a qualified teacher.