Watch the Melody Technique 1 online guitar lesson by Tierra Negra from New World Flamenco
When playing arpeggios, we don’t rest any part of the right hand on the guitar body - the hand floats in the air. To play melodies, however, we typically do rest a finger or thumb on a string or the body of the guitar. This provides some extra stability that comes in handy when playing melody.
In this technique, for example, we will use a "rest stroke." Immediately after plucking each string, rest the finger on the next string. In other words, if you pluck the high E with the index finger, rest the finger on the B string.
You will also rest your right thumb on the low E string to stabilize your hand. This technique gives you more power and attack. Play the melody with the index (I) and middle finger (M) of the left hand.
Note that I do lift the thumb from that low E string as I play the C scale. I let my right hand move vertically up and down as I play the scale.
During this movement, my thumb is always touching the top of the guitar.