Stand tall with an upright posture. This allows you to utilize the muscles in your abdomen in order to support your breathing.
Place one hand on your upper abdominal area. Take a slow, deep breath and focus on contracting these muscles gently as you exhale. Do this several times to get a feel for it.
Take another slow, deep breath and sing a syllable like "ooo" or "ahh" softly as you exhale slowly. You should be able to vocalize for about 10 seconds from one breath. As you practice, increase the vocalizations to 20 or 30 seconds.
Sing a familiar song while practicing abdominal-supported breathing. Take breaths at breaks in the song, such as places where periods or commas appear. Breathe slowly and deeply at instrumental breaks in the song. Keep your body relaxed to maximize your breath potential.