In the following practical exercises, try to concentrate on what your breath is doing and how it feels as you inhale and exhale. There is no better way to see (& feel) what we are talking about unless you do it.
Be sure you are in a comfortable location before you begin. It is not only important to be relaxed, but breathing exercises can cause some tiredness or even dizziness. If you start getting tired, know that you can practice more a little later once your energy returns. The worse thing to do when learning how to sing is to overwork yourself, your breath, and your voice.
Start out by lying on your back. If you have a yoga mat, or something soft enough to be comfortable, use it, but whatever you use should be stiff enough so that your hind does not sink inward.
Now, place your hands on your waist so that you fingers are pointing towards your navel. Be sure your hands are relaxed. As you breathe inward, try to fill up the bottom part of your diaphragm or stomach first. Your hands should slowly rise and fall with each breath. Don't fill up your cavity to the point of pain, but inhale so that you can feel the expansion of your chest, sides, and back. Remember we discussed early about your chest cavity? Well, this also includes the back portion of your thorax. You should also feel it expand.
Following, try to breathe out slowly to a count of four or five. And, try to repeat it five to eight times. If you start to get light headed, just take a break. This exercise should relax you and start giving you the skills to control your breath without having to actually focus on properly using your diaphragm and air space each and every time.
This exercise should be done in the morning and in the evening. Try to plan a two-week period where you do it everyday for five to ten minutes each session. Then, as you progress, attempt to do so three to five times per day. And, as you continue, you might try singing the numbers out loud, as you slowly release your breath. Keep the numbers that you sing at one pitch and increase the amount of numbers that you count down from five to ten to fifteen over the weeks.
Another exercise you should do once you have gotten to the point where your breath is more easily controlled and where you do not feel light-headed or dizzy is one that can be done while sitting at work or at home. It is a simple formula that should always be kept in mind: the more you practice your breathing, the more control you will have over your voice and the sounds emitted.
So, as you sit with your abdomen and back straight with excellent posture, inhale for a count of three.
This is similar to the exercise where you are laying flat, except this one should be done once you fully understand and properly feel how your diaphragm is working and where the air is being stored. This exercise should be done with the other, through the day, when you cannot lie down.