Use correct posture when singing. Stand or sit with your back straight, your neck elongated and unrestricted and your head held high. This will ensure that you achieve proper airflow allowing your voice to amplify as much as possible.
Relax your jaw and tongue. Tension in this area will restrict the natural vibration of the vocal cords causing them to lose volume and produce a weak tone.
Breathe through the diaphragm when you take a breath and ensure that you take in air throughout your entire midsection. If your midsection does not expand, you are not taking in enough air to support your voice.
Sing in tune by matching your pitch with a piano or recording. Failure to sing in tune will make your voice sound dull and lifeless.
Pronounce the vowels and consonants in each word clearly to ensure that your diction is clean. The best voice in the world will sound weak if the words are not crisp and clear.