Explore the capabilities of his own voice. Define the parameters for your vocals: power, range, tone. Please contact the teacher or a professional musician for advice. Listening will not take them much time, and you don't have to pay for a trial lesson.
Check out how the work of the respiratory muscles. Put your hands on your stomach and take a few breaths. Imagine that you inflate an imaginary fire. If you do not feel like rising and falling stomach, then you are not breathing diaphragmatic and clavicular, wherein the volume of air is consumed irrationally.
Learn to breathe properly. Put your hands on your belly and raidmates. Feel where and how to tighten the abdominal muscles. Remember their position. Take a slow breath in, count to four and slowly exhale to the same count. If you have not felt while working the abdominal muscles, tilt during this exercise the body forward and place your hands on the lower back. Continue to implement it, increasing with every inhale-exhale account for one unit (5,6,7, etc.).
Select a suitable room for doing vocals. For example, it is not necessary to practice singing in a room full of soft furnishings, as the sounds will be muted, and you have to constantly strain your vocal cords. And it is unsafe even for a professional singer.
Warm up before class breathing apparatus. Sit on a chair, relax the muscles of the shoulder girdle and neck. Do the exercise, breathing in for one and a half minutes, his mouth alternating a quick breath. Ensure that shoulders are not raised. And only after that proceed to the pre-chorus, performing during it any ringtone for any vowel (usually A or O) or syllable (e.g. "LA"). Gradually increase the strength of the sound, but do not strain.
Select a song, the melody and text of which are well known to you. Make it a "minus" entry. Listen to the original version. Then sing it first without musical accompaniment. Put a "minus" track, and perform it several times, specifying all of the occupation. Listen to the recording. If you think she's not too good, sing during classes first together with the real singer of this song, paying attention to how it works voice. And then the "minus" or a Cappella. Don't forget to record every lesson to understand in the right direction whether you are working with.
Practice no more than 30-40 minutes a day. Do not force the sound, especially at the initial stage. Don't try to "go" to get too high or too low notes. If you feel that the voice of "sit down", reduce class time by 5-10 minutes until, until he recovers.