So that method where you hold the 5th fret low E and play the A string, and so on etc…
What are you listening for?
As far as I know you are listening for a beating or wobbling, and you keep tuning untill there is no discernable beat. Is that right?
Is there anything else to that?
And if thats all there is, what way do you tune when the wobble is fast, or slow?
Just Wana hear your experience in it and confirm my understanding 
Nowadays I almost always use a clip-on tuner (or the Peterson phone app “iStrobosoft”).
But I used to (even though it’s incorrect) use 5th and 7th fret harmonics and tune the 7th fret natural harmonic on the A string to the 5th fret natural harmonic on the low E string, then tune D string to the A string (harmonics), then the G string to the D string (harmonics), then tune the D at the third fret of the B string to the open D string, and then tune the high E string to the E at the fifth fret of the B string. Don’t recall which way now, but I think I’d also adjust the G a little more sharp or flat afterwards to sweeten chords.
And yes, the beats reach a maximum rate a short pitch distance away from the target note, then slow down and approach zero as you home in on the target note (and will start to increase it again if you pass it).
Also, most consistent tuning results come from tuning up to pitch (approaching the target pitch from the “flat” side). If you tune down to pitch, sometimes you will end up with extra slack caught up somewhere along the chain, only to get released and flatten the pitch later.
Regarding “wobble,” aim for as slow as possible. You can use your tuner to confirm this with experiments.
I would take this a step further and say you shouldn’t hear any discernable modulation if tuning this way, at least once you’re in tune. A fast “wobble” means you’re not close, while a slow one means you’re getting pretty close.
Also, I personally prefer to use 5th / 7th fret harmonics to tune, in case you haven’t tried it.
Also also, something that has helped me is to tune by ear first, then just check with a tuner to see how far off I was.
Even tempered tuning is always going to be off and have some warble. I tune my A string and tune everything else relative to it. Even tempered instruments are never going to be exactly in tune and better to just tune the instrument to itself imo.
This may seem convoluted at first…but 30+ years of doing this, it’s never let me down when I need it. I use a modified version of tuning to a string that (I think) I learned from Eric Johnson. IMHO - it doesn’t get discussed enough. Either that - or everyone does this and I never knew. ¯_(ツ)_/¯
With this method, every string uses the A string as a reference. This prevents slight variations from stacking as you match strings.
This should go without saying, but we live in a Warning Label world…All this does is tune the guitar to itself. If the A string isn’t at 440 (or whatever) - it won’t be in tune with other instruments. So, get the A string up to pitch and to tune the…
E string: Pluck a harmonic on the A string, 7th fret. Let that ring and pluck a harmonic on the E string, 5th fret. Its the same pitch - tune the E to match the A. For me the harmonic makes it much easier to hear the beating/wobble.
D string: Harmonic on the A, 5th fret. Harmonic on the D, 7th fret. Mach tones.
G string: A string, 12th fret harmonic and let ring. Fret the G string at the 2nd fret. Same pitch - tune the G to match.
B string: A string harmonic, 7th fret. Fret the B, 5th fret (again - same tone)
E string: A string, harmonic at the 7th fret, High E open. Once again - same tone. Tune high E to match.
All 6 strings are now in tune with the A as a reference. Specific intonation may have you adjusting something. In my experience, if its more than one string (G or B, usually), start over.
EVH was said to tune his B string slightly flat to make chords sound better with distortion. So you’re not nuts if you do something like that.
Hope this helps someone.
I mean, the “wobble” is pretty incidental here - you’re listening for the pitches to match. If you can’t tell if one’s sharper or flatter than the other, you should be using an electronic tuner.
If I use this approach, or the “match the 5th fret harmonic to the 7th fret harmonic of the next thinner string” one, I’ll also go back and check octave points - like, booth open E strings and the D string 2nd fret, and then A strong 2nd fret B against open B, E string 3rd fret G against open G, etc.
Truth!
If this guy says he has to use a tuner, I’m fine with using a tuner too lol!
He mentions if he doesn’t have a tuner he gives his guitar to someone else and has them tune it haha! One of the all-time greats 
Quite at odds with the premise of the OP for sure. I do think it’s good to have the ability to get in tune by ourselves though. There will be some time when there’s no tuner available and no other ‘person’ available to tune our guitar for us.
Agreed, as slow as possible is hopefully 0Hz (= none).
A human is supposedly good to six cents or so, but my electronic clip-on tuner claims to be good to 0.02 cents, crushing humans. But it gets worse for humans: By tuning string-to-string, it is possible to pick up additional cumulative error (unless one attempts what @Ruefus suggests, above). Electronics view each string individually.
The summary is simple: Use a machine to tune. Of course, if there is a three-year-old genius with perfect pitch floating around, that would be my choice:
According to the accounts, when Mozart was a young child, around the age of three or four, his family paid a visit to the residence of the Archduchess of Austria, Maria Theresa.
During the visit, Mozart noticed a violin lying on a table. He was immediately captivated by the instrument and expressed his desire to play it. However, his father, Leopold Mozart, told him that the violin was out of tune and it would be impossible for him to play it in its current state.
Undeterred, young Mozart insisted on giving it a try. He requested the violin, and to everyone’s astonishment, he managed to tune it by ear flawlessly. This amazed the Archduchess and other witnesses present, as the skill of tuning an instrument accurately was typically associated with seasoned musicians.
On the tuner thing, I agree it’s more accurate, tho I really want any help in training my ears.
That Mozart story is pretty cool. Make you wonder how it’s possible, especially since he was so young, perhaps the parents were making him learn music for a few years already? Idk much about him.
Why is it incorrect?
My GF has perfect pitch, and it makes her incredibly annoying. If something is playing on Spotify, I can ask what the key is, and she’ll go through some dramatic eye-rolling (meaning, “I can’t believe that you don’t know”), and then tell me.
Regarding Mozart, I don’t know if it is nature (total genius), nurture (his father taught him from an early age), or both, but he is worth reading about and listening to. His study of a popular French song (twinkle twinkle little star) is worth listening to if you haven’t heard it before. There is also a movie about him (that surely is mostly fiction), Amadeus.
Man you must try to hide from her while playing lol
Short answer:
Because the 7th fret harmonics don’t quite correlate perfectly with the pitches we are supposed to tune the guitar to.
Long answer:
Because a guitar typically has frets, we are bound to a system of tuning that is applied in the design and spacing of the frets. That system is called “equal temperament”. In a nutshell, it’s mathematically impossible to have a tuning on a fretted instrument where all musical keys are perfectly consonant, and if you make one key as close to perfectly consonant as possible, other keys will become much more dissonant. Under the equal temperament approach, no single key is perfectly consonant, but all keys are equally “slightly dissonant”. What this means in practice is that the guitar is designed with the intention that the ratio of frequency between any two adjacent semitones is always the same. That ratio is expressed numerically as the 12th root of 2 (or 2 to the power of 1/12), frequently approximated as 1.059463.
Taking the low E and A strings as examples, for equal tempered tuning based on A4=440hz (aka “standard tuning”), the A string of the guitar should be tuned to 110Hz. By the math of equal temperament, this demands that the low E string be tuned to roughly 82.407Hz.
Let’s suppose you are starting out with a low E string correctly tuned for equal temperament, at 82.407Hz.
The frequency of the 5th fret harmonic of that string is 4 times the fundamental frequency: roughly 329.628Hz.
If we tune the 7th fret harmonic of the A string to 329.628Hz, the fundamental of the A string will be that frequency multiplied by 2/3, and then divided by 2, resulting in 109.876Hz. This is flatter than the correct frequency for the A string in standard tuning: 110Hz. To correctly tune the A string to 110Hz using the 7th fret harmonic, we’d have to be matching the 7th fret harmonic to a reference pitch of 330Hz, but that’s sharper than the reference pitch available from the fifth fret harmonic of a correctly tuned low E string.
Another way of thinking about this is that if you have a correctly tuned A string (110Hz), the 7th fret harmonic will ring at 330Hz, which an electronic tuner will complain is slightly sharper than the nearest note in equal temperament (an E with frequency 329.628Hz).
So the “tuning with harmonics” approach results in an A string slightly flatter than it should be. Then if you tune the D string to the A string using the same approach, you are going slightly flat again, and worse, you are going flat relative to a reference pitch that is itself flatter than it should be. And same thing if you then tune the G string to the D string.
So even if you start with a perfectly tuned low E string, the “5th and 7th fret harmonic” approach leads each successive string further and further flat from their correct “equal temperament” pitch.
And it can get even worse: tuning the B string to the low E 7th fret harmonic, it ends up sharp (by ~2 cents) with the flat (by about 6 cents maybe) G next to it.
I still tune with harmonics sometimes, but I widen the intervals between the lowest 4 strings and narrow the E 7th harmonic to open B interval. If you tune normally with an actual tuner and check harmonics afterward you can get an idea of what each beat frequency should be. It changes with the pitch of the harmonics used so the rate increases as you go up the low strings, then E 7th fret harm. to open B should be slower than any of the previous ones.
Guitarists spend half their time tuning their guitar. The other half, they spend playing an out-of-tune guitar.
If you are tuning by ear just as an exercise in tuning by ear, you might try doing it the way I did it all my life until around 2011 when I got a Peterson strobe tuner. I learned from records and part of that process was learning to tune my guitar’s strings to the pitches heard on the recording I was studying. The methods that Frylock and Ruefus mentioned are accurate and similar to how I tuned for around 40 years. This will almost always result in a tuning offset which is slightly off from direct chromatic pitch…which is a good thing. It is important to understand that once a guitar has been set-up/intonated to direct chromatic pitch with a strobe tuner, you really must use tuning offsets to get your guitar as in tune with itself as physics will allow. Unless you seek a physical remedy like a guitar with TruTemperament zig-zag frets, this is just what people do with regular guitars.
Here’s a great video in which Eric Johnson demonstrates his tuning technique which is essentially identical to what I did myself for 40 plus years before I got a Peterson. I checked EJ’s results with my Peterson StroboPLUS HDC strobe tuner and as it turned out he tuned by ear to exactly -30.0 cents below standard chromatic pitch. Which is about - 1/4 step. Which is pretty damned amazing. EJ Mini Lesson 10 - YouTube
Do you have the video link?
That’s great, I just discovered that all the different ways I ever tried to tune a guitar “by ear” were wrong 
Another hilarious thing: for years I had this automatism that after tuning the guitar I would strum an open position E major chord to check if it sounded good.
Spoiler: with the guitar tuned correctly, an E major does not sound good
PPS: with a fast electronic tuner you can also easily measure that the (initial) pitch of the string changes depending on how hard you pick the string. I’m not talking subtle changes, but something like 20-30 cents difference between picking softly and hard.
So, you can’t even tune in a way that will work for a single string in all situations.
It’s just maddening the more you look into it.
Now I just record stuff with bad tuning and hope that no one notices.
I remember one recording session years ago. We had to record the song chord by chord. Tuning for each individual chord. It was a major pain in the ass, but just couldn’t get it sounding good any other way. Any time I feel like I miss recording, I just think of those times 
In hindsight, I’ve realised that you can very much get away with being a little bit out. Most people will not notice or care and ears tend to adjust to the sound pretty fast. Unless it’s way off of course!