Relax before performing vocal exercises. Tension and stress will cause the vocal cords to tighten and will prevent you from being able to sing in a full range. Create a big smile on your face and hold it for one minute. This exercise will help to relax the body.
Drink water to moisten the vocal cords. Dry vocal cords resonant less.
Yawn deeply to relax the larynx. Let out a siren sound: "wooo" or "weee." Feel the sound go up into the cavity of the head. This exercise will help you to open the vocal cords.
Sing "Gi" in scale. This will help to strengthen the larynx to properly close the vocal cord. Don't force the high notes. Reduce any strain in your throat.
Place the finger on an area of the neck covering the larynx. Begin to yawn, then say the word "dumb." Feel the larynx descend as you say this word. Sing and repeat "dumb --- dumb --- dumb." Allow each "dumb" to be in a higher note than the previous word. This will strengthen the larynx which controls the vocal cords.
Speak the word "mum." Sing this word in a scale. Don't allow the word to get louder as you go higher in the scale. Stop at the first sign of strain. This will help open the vocal cords and improve resonance.