This generally involves training in breath control and support, proper tone production, pitch control and musical intonation, proper formation of vowels and consonants as well as clarity of words, attentiveness to musical notation and phrasing, and the learning of songs
My teaching experience is 30+ years. I received my education in Russia. I was lucky to study piano and voice disciplines under really good teachers. They gave me a good understanding of music, good taste of it, and real professional training.
What technique do I teach?
I teach my students a technique I've been taught. Technique of good bel canto traditions which famous Italian singers used at the end of 19th and beginning of 20th century.
There is no magic, it takes time, and it takes both-my knowledge and students enthusiasm. I start with exercises to find out student's range. Then little by little try to increase it.
Deep diaphragm support is very important. I don't want to make it too complicated, therefore trying not to spend much time on physiology. Depending what level is a student choose the right warm up. Always encourage my students if there is even a small improvement.
Asking them to bring recording device they could listen a lesson after and analyze it.
After several month of working on range, breath control, phrasing, diction, it is time to start thinking of the right repertoire, time to apply their knowledge to the music.
Except the right technique, the musical taste is very important aspect.
Overall I learn with my students and I am very thankful to them for helping me.