Learn the lyrics and the melody of a song you want to sing.
Sing that song in the vocal range that feels comfortable to you.
Think of attracting someone's attention without disturbing others.
Marshal all your forces and focus them mentally into one beam of sound.
Sing at moderate volume first, then as softly and beautifully as you can.
Send your voice forward like a beam of light that reaches the farthest seat in the gallery.
Color the note you are singing with your innermost feelings.
Launch your voice forward with a great burst of energy without forcing it. As soon as you feel discomfort in your throat, you are forcing it.
Allow the passion of the moment to direct your voice - don't just turn up the volume.