Remember that on the faithfulness of sustained vowels, and the clearness and delicacy of consonants depend your best vocal quality. You cannot realize either without feeling and looking what you sing.
Do not allow your vowels to weaken in pronunciation. Make them more and more acute the longer you hold them.
Soften the tones of consonants – let them sing themselves by the sighing of the naturally expiring breath.
Do not think about your tongue – your mouth positions will regulate that member unconsciously in singing, as in speaking.
Do not trouble about how you shall breathe. Many so-called breath gymnastics I have found to be positively harmful to students. You should learn how to breathe without knowing it by singing. Practising breathing without singing is useless to the vocalist.
Do not hit under your notes: In vigorous passages attack them suddenly and squarely on pitch. In soft phrases attack squarely, but with gentle contact. In either case increase the tone slightly after attacking the note.
If it becomes necessary to glide from one note to another, do not impart much tone to the slur.
Do not allow the voice to wobble or become tremulous.
A tremor is dangerous under any circumstances, and an ineffectual substitute for sustained, pathetic tone color.
If you want pathos, use the tearful note – cry, or sing as though crying.
If you want brightness, smile. You cannot do this without sunshine coming into your voice.
Master the legato flow. Imitate the smoothness of the church organ.
Breare, William Hammond. Vocal faults and their remedies. Simpkin, Marshall, Hamilton, Kent & Company, 1907.