Breathe from your diaphragm
Speak more slowly
Relax your throat and jaw
Keep your posture upright
Lower your larynx naturally
Hum in a comfortable low range
Practice vocal warm-ups daily
Avoid straining your voice
Stay hydrated
Reduce excessive caffeine and smoking
Use resonance in your chest
Record and monitor your voice
Work with a vocal coach
See a doctor if your voice changes suddenly