Use a tuner or tuning app
Start with the low E string
Tune the low E to E
Tune the A string to A
Tune the D string to D
Tune the G string to G
Tune the B string to B
Tune the high E string to E
Turn the tuning pegs slowly
Tighten the string to raise pitch
Loosen the string to lower pitch
Check each string again after tuning
Repeat until all strings are in tune
Use harmonics or the fifth-fret method if needed
Stretch the strings gently and retune
Tune with the guitar in playing position
Recheck tuning before playing