Breathing is a very important technique in singing. The singer needs to sustain long phrases, sometimes for fifteen or twenty seconds, he obviously needs a considerable reserved of breath [air]. This can be taken in only by using all the capacity of the lungs. 

The lungs are pear-shaped-wider at the bottom than at the top. Everyone uses the narrow upper part, but the broad parts at the bottom are rarely exercised. To fill them completely you have to concentrate on the base of the lungs- not the upper chest.

Air goes in and out of the lungs when we are singing, before I go on to talk about breath support and breath control, I will want us to understand what really go on when we are breathing and how we apply it when you  are singing.

Try this exercise to begin with: standing with the fingers of both hands pressed into your sides at waist-level, slowly and easy take a deep breath, concentrating on filling-up from the bottom of the lungs [you may find that breathing through the nose makes for a fuller, deeper breath, and of course, it warms and cleans the air, making it less harsh on the throat.] Think of it as an extension of ordinary breathing: ‘feel’ the air going down, deep into the bottom part of your lungs.

If you are doing it properly, your hands will be eased out. This is because the lungs should expand downwards as well as well as sideways, and in doing so, the muscles underneath are flattened and pushed outwards, by the way, if you have recently eaten a large meal, you stomach will prevent these muscles from moving freely, and you will not be able to expand easily but experience a sensation of tightness.

If you are not used to doing this kind of breathing, you may not be able to expand fully at first. No one I have known has been able to do it at the first attempt and women seem to find it more difficult than men. But with patience and steady practice it will come right. You will eventually ‘sense’ the correct way to do it and you will feel and see the increased expansion.