Mark Clark, I'm with you on tuning by ear, but I'm not good enough to hear the open intervals (that is, I haven't practiced enough!) I use a method taught to me by John Knowles, in which you tune each string in turn to the A string: (1) Tune the A string to a 440 tuning fork. (2) Hit the 12th fret (octave) harmonic on the low E and match it to the 7th fret note on the A string. (3)Hit the 12th fret harmonic on the A string and match it to the 7th fret note on the D string. (4) 12th fret harmonic on A string matched to 2nd fret note on the G string. (5) Tune the B string to the 2nd fret note on the A string. (6) Tune the open high E to the 7th fret note on the A string.

Yes, I know it's not perfect. You have to know how to play a harmonic (pretty easy to learn), but more importantly, it assumes that the instrument's intonation is accurate enough that the 2nd and 7th frets are in the right place. But if they're not, no method is going to work. The advantage of this method for me is that you're tuning unison pitches, which makes it much easier (for me at least) to hear the beats, or just to hear when they're identical if you can't catch the beats.

My soon-to-be-ex-wife always used to rib me because I had an electronic tuner but never used it. In a noisy room, though, I went with the black box every time.

Aloha,
Mark