Perform tongue twister exercises. Try articulating and repeating tongue twisters such as: "A proper cup of coffee in a copper coffee cup" and "the lips, the teeth, the tip of the tongue." Use as many as you can to build up your skill. Tongue twisters prepare your mouth and brain to focus on articulation and pronunciation -- both of which are vital to volume and projection. The more you articulate, the easier it will be to transition from lyric to lyric and the clearer the words will be to your listener.
Position your body correctly. Stand up straight. Relax your neck, head and limbs. Lift your head so you are looking straight out or slightly tilted upward at a diagonal angle. Maintain this position as you sing to keep your lungs open and to eliminate body energy from constricting via poor posture or excess tension.
Master your breathing. Practice singing on one breath of air for at least four solid measures. Select a point -- every four measures -- to inhale fresh air. The only way to ensure your lyrics will be projected and heard is to ensure your breathing complements your notes and measures. Choosing a spot every four measures builds your breathing muscles and prohibits the breakup of rhythms and lyrics.
Press air out from the diaphragm. Tighten your abdominal muscles to engage the diaphragm while you sing. The diaphragm is an umbrella-shaped muscle underneath your rib cage. Singing from the diaphragm allows you to project, resonate and save the clarity of your voice in a way singing only from the chest and lungs cannot.