Determine the vocal range appropriate for your voice. Sing along with recordings or a musical instrument to determine whether you are an alto, baritone, bass, soprano or tenor.
Sing scales or other vocal exercises to properly warm up your voice. Also drink warm tea, water with lemon or coffee before singing. These fluids literally warm and lubricate your throat and vocal chords before you start singing.
Practice the vocal-fry technique. Although it may sound like screaming or yelling, proper metal singing doesn’t strain or injure the vocal chords. The sound is a slow vibrato that should emanate from the back of your throat. Your vocal chords should vibrate very slowly. Never use force on your voice when singing metal.
Practice making higher sounds emanate from your nasal passages rather than deep in your vocal chords. This will help prevent injuring your voice.
Sing from your diaphragm. Fill your abdomen with air and push air out from there, rather than from your lungs and chest. Place your hand over your abdomen and feel the air expand the space to be sure you are breathing properly.
Progress in volume slowly. Practice singing softly and progress to louder and louder sounds when you’ve perfected the technique and sound.
Record yourself singing. The best way to evaluate your sound is to record your practices and play them back.