HABIT ONE: CREATE SPACE
Lungs need space to work properly. Place the fingers of your right hand on your breastbone and your left hand underneath your belly button. Slump, then gently lift your top hand and ribs away from the bottom hand without swaying your back. Breathe out and relax the shoulders. This lengthens your torso and correctly activates your deep core.
HABIT TWO: USE YOUR BASE
Breathe in through your nose for a count of four to fill the base of your lungs without moving your breastbone. When you feel the air reach your lower lobes, imagine your diaphragm, which is at the base of your ribs, is an umbrella. As you breathe in, feel your bottom ribs expand at the front sides and back. Breathe out to a count of four and imagine the umbrella is slowly closing and drawing in your ribs and stomach wall. You'll feel your stomack deflate like a soufflé. Keep your chest up. Repeat for 5 slow breaths
Changing breathing habits will take time. It's a good idea to practice at every oppurtunity (While watching tv, or standing in a supermarket que. Once the habit is ingrained, there are positive flow-ons into daily life.
As you breathe out, the stomach wall should draw in. If the stomach bulges or hardens or you hold your breath, the core has crashed, along with the support.
If you can get the foundations right when standing, sitting, walking and breathing, you will be able to achieve much more when undertaking more complex activities, such as exercise. The other bonus is that you will look better when your posture is aligned and feel better through boosting your confidence & activating your body's internal elastic support. You'll be surprised at how much your progress improves when your posture is aligned and you start breathing better.