Watch the Danny Boy: Single String Melody online guitar lesson by John Knowles, C.G.P. from Fingerstyle Journals
I decided to let the melody speak for itself at the beginning of "Danny Boy". I play it on the 3rd string so I can hear the harmonics on the 4th, 5th and 6th strings ring. To make it work, I have to tune carefully so that the third string will make the harmonics on the bass strings sing out. Then, I worked on the fingering to minimize the sound of shifting up and down the third string. I want that melody to sound like singing.