Learn the notes on the sixth string, E, and fifth string, A. Identify the fretboard markers and memorize the corresponding notes on the sixth and fifth strings.
Learn the octaves to the notes on the sixth and fifth strings. The octaves are found on the fourth, D and third, G, strings. Once you learn the octaves, identify notes on the fourth and third strings by referencing the lower octaves.
Play the second string, B. from the third fret. The third fret of the second string is the E note, which corresponds to the sixth string. From the third fret, the notes run chromatically as the sixth string from the first fret.
Locate the 12th fret marker. The first fret to the 12th fret and the 12th fret to the last fret contain the same note arrangement on all sixth strings. It's basically a copy of the first twelve frets.