A singing voice improves through vocal exercises, which include singing scales, practicing breath control and matching pitches. These exercises are most effective when directed by a vocal coach.
The sound of a singing voice changes based on the singer's control of air from the lungs, diaphragm and chest, the vibration of air through the vocal cords, and the resonance of air through the nose and mouth. Pitch control improves by listening to a note and then practicing reproducing it. Vibrato of a note comes naturally with practice.
To sing well, a singer should maintain vocal cord health by eating healthy foods, staying hydrated and getting enough rest. It is important to avoid overusing the voice, screaming and smoking. Vocal coaches teach voice control, while singing voice specialists and speech pathologists can help with voice rehabilitation.