Above all sing spiritually. Have an eye to God in every word you sing. Aim at pleasing him more than yourself, or any other creature. In order to do this attend strictly to the sense of what you sing, and see that your heart is not carried away with the sound, but offered to God continually; so shall your singing be such as the Lord will approve here, and reward you when he cometh in the clouds of heaven.
On how to sing hymns