Become familiar with how the tuning pegs cause the pitch of the string to move up and down. Strike the thickest string, known as the low E string, and then slowly turn the tuning peg for that string. You will notice that the tighter you make the string, the higher the pitch. This is the case for all of the strings. For the sake of convenience we will refer to the low E string as string 1, the string below it as string 2 and so on to string 6.
Strike a low E tuning fork on a hard surface and then turn the tuning peg until the sound of the strummed string matches the pitch of the tuning fork. If you do not have a tuning fork then use the MP3 files found on the resource site listed below.
Place your finger in the fifth fret of string 1 and then strike that note. That is the note you will tune string 2 with. Turn the tuning peg on string 2 until it matches the pitch of the fifth fret on string 1. Repeat this with string 2 to tune string 3 and string 3 to tune string 4.
Place your finger in the fourth fret of string 4 and tune string 5 to that pitch.
Place your finger on the fifth fret of string 5 to tune string 6. Be sure to carefully turn the tuning pegs of the last two strings because these are the thinnest strings and if you turn them too tightly they will snap.
Repeat these steps one more time to confirm that the guitar is in tune, and then strum all of the strings at once. If the guitar still sounds out of tune, start at step 1 and repeat all of the steps until the guitar is in tune.