May be freely copied and shared for any educational, noncommercial purpose. You'll play better if you breathe deeply and correctly. To check this, place your hand on your stomach. As you inhale and your lungs expand, you should feel your stomach push out.
Many people do the opposite, holding in their stomachs and breathing only with their upper chests.
Practice holding single notes long and steadily. Pull in your stomach in short jerks, as if belly-laughing. You can use vibrato to enhance long notes.