When singing, the muscles of the throat must be relaxed, not contracted. Self-consciousness often does more to mar a good voice than anything else, since it leads to the contraction of the muscles.
Have you ever noticed how pleasantly some people sing or hum to themselves when they imagine they are not overheard, compared with the indifference or even unpleasant manner in which they perform publicly?
Here we have a direct example of the result of self-consciousness. Never mind your audience. Allow the song to carry you away, so that you sing easily and naturally.
To acquire perfect control over the throat muscles, so that they may be relaxed at will, is one of the most difficult points in voice training.
Dame Clara Butt (1872-1936)