Produce the sound from your mouth. This means getting the sound production up front, out of your chest and your throat — and definitely out from behind your nose! Try humming a sustained, comfortable note. Feel your throat, then further up at the back of your jawbone and finally right beside your lips. You should feel the strongest vibration at the lips. If it's anywhere further back, you're swallowing your voice and it gets muffled and dull. Buzz your lips. Feel where the energy's going from? Now open your mouth without letting the sound drift back. Sing a simple song - "Mary Had a Little Lamb" will do - while focusing on keeping the sound at the front of your mouth. With practice your voice will get brighter and you'll waste less energy trying to push the sound out. The shower is a great place to practice!