Tuning a guitar by ear is a great thing to learn to do. It enables you to not have to depend on a guitar tuner for tuning.
Tuning a Guitar By Ear – Walkthrough
1 – Since theres no tuner you’ll be tuning the whole guitar to the low E string. Try your best to have the low E string as close to properly tuned as you can.
2- Put your first finger on your left hand on the 5th fret of the low E string.
3- Now strum just the low E string with your finger on the 5th fret. You are now playing an A. This is the same exact note that the next string should be when played open.
4 – As you play the 5th fret on the low E string alternate between that and playing the A string open.
5 – Now adjust the A strings tuning peg in order to match the tone of the 5th fretted low E string.
6 – Repeat the process for the D and the G strings. To tune the D string you put your finger on the 5th fret of the A string and play the D string open. For the G string you put your finger on the 5th fret of the D string and play the G string open. Are you seeing the pattern here 
7- Heres where it gets tricky. In order to tune the B string you have to move your finger to the 4th fret of the G string (not the 5th fret this time). The G strings 4th fret is the same not as the B string played open.
8 – To tune the high E string we go back to the old pattern and place our finger on the 5th fret of the B string which will be the same not as the high E string played open.
Congratulations you’ve just learned the secrets of tuning a guitar a guitar by ear!
