Proper breathing is vital to good singing. Because the vocal chords react to air movement, singers must be able to carefully and efficiently control the flow of air. Proper breathing involves using the diaphragm to control the abdominal muscles as air is inhaled and exhaled through the lungs.
While there are many breathing exercises to try, a simple, effective warmup exercise involves sitting or standing with your upper body in a straight but relaxed state. Exhale and move your ribcage to a slightly raised position. As you inhale, concentrate on keeping your ribcage in the same position and expanding your diaphragm as you take a breath. Hold the breath three seconds, and slowly move your diaphragm into your abdomen to help expel the breath. Repeat this exercise until it becomes automatic, as it will likely feel unnatural at first. This warmup helps build the diaphragm muscle and helps you to become conscious of its role in the breathing process.
The jaw and lip muscles play an important role in singing and need to be totally pliable and relaxed. To warm up and loosen jaw muscles, open your mouth slightly and concentrate on relaxing the muscles. As they relax, your jaw will drop and you may feel your tongue wanting to protrude. This is a good sign that the muscles are relaxing. With your jaw open and relaxed, move it slowly and evenly from side to side, with your fingers gripping your chin. Continue with this warmup exercise until you feel no tension or tightness when your jaw is closed.
To warm up your lip muscles, relax and purse your lips slightly, and make a simple "motorboat" sound. It will feel funny at first and be a bit challenging, but keep trying. Once the muscles are relaxed, you will be able to produce this "trill" sound with no problem. As you progress, vary the flow of air slightly. Less air will give a slower trill, with more air causing the trill to become faster.
When your breathing is under control, and your facial muscles are warmed up and relaxed, it's time to sing. Everyone has a midrange singing voice that comes naturally and is similar in pitch to your speaking voice. This is the pitch you want to start with.
Sing the scale--do, re, mi, fa, so, la, ti, do--forward and backward slowly and at a comfortable volume four or five times. Raise the pitch very slightly, using the "re" pitch in the scale as a string point for the next series of scales, and continue going upward in pitch. When your voice becomes hard to control and approaches your "head" or "falsetto" voice, start doing the exercise again at a similar starting pitch. Rather than raising the pitch upward for subsequent scales, move the pitch downward. When your voice becomes hard to control as you move down in pitch, it's time to stop and work on the same exercise using your falsetto or head voice.