Electric guitars

1st	E	Tune open string to pitch
2nd	B	Tune open B string (2nd) to open E string (1st), until they are "beatless"
3rd	G	Press the 2nd fret A, and tune that note to the open E string (1st) "beatless"
4th	D	Press the 14th fret E, and tune that note to the open E string (1st) "beatless"
*5th	A	Play the 7th fret harmonic, and tune that unison to the open E string (1st) "beatless"
*6th	E	Play the 5th fret harmonic, and tune that unison to the open E string (1st) "beatless"

* Once you're tuned the A and low E string (6th) using harmonics, check the A by playing a 2nd fret B note and check that octave with the open B string (2nd).

*Check the low E string (6th) by playing the 7th fret B note and check that octave with the open string B string (2nd).

Acoustic guitars

1st	E	tune open string to pitch
2nd	B	tune open string to open E string (1st) "beatless"
3rd	G	press the 9th fret E and tune to open E string (1st) "beatless"
4th	D	press the 9th fret B, and tune to the open B string (2nd) "beatless"
*5th	A	play the 7th fret harmonic, and tune to the open E string (1st)
*6th	E	play the 5th fret harmonic, and tune to the open E string (1st)

* Once you're tuned the D string using the fretted B note, check the 2nd fret E against the High E string (1st) octave. Once you're tuned the low E string (6th) using the 5th fret harmonic, check the open low E string (6th) against the 2nd fret E note on the D string.

If you are close to being in tune, sometimes it's hard to tell if a fretted note is sharp or flat. Try bending the note slightly. If it gets worse, (more beating) it's a little sharp, if it gets better it's a little flat.

DO NOT USE THE OLD METHOD OF COMPARING THE FRETTED A, D and G with the open A,D and G. It is not as reliable and it is more difficult to hear. Also, stay away from harmonics except as described above; they are also unreliable.

12 Strings:

1. Tune the 2nd string of each "pair" of strings using the methods described above.
2. To tune the 1st string of each pair (octave), tune the 1st string of each "pair" to the second string of each pair, "beatless".