The idea is to move your hand as little as possible. Find the points where you absolutely must change left hand positions, change and then try to stay at the new position as long as possible before changing again. Once you do have to move, think about the previous couple of fingerings. As the open string rings, you simply move your hand to the next position. Make sure you don't make noise as you slide your hand or allow other open strings to ring out.
Harmonics are natural vibrations of the strings that produce a certain pitch.
The sound of a harmonic is kind of a bell sound and usually sustains longer than a fretted note. How To Play Harmonics To play a harmonic, place a finger directly over the 5th, 7th, 12th, 17th, or 19th fret. Just barely touching the string. Don't press down to the fret board. It is a very fine touch and this is going to take some practice to get the harmonic to chime loudly so try using less and more pressure on the string.