Advanced Guitar

As an advanced guitar player you should have mastered the concepts of the beginning and intermediate player and then also be able to do the following:

Tuning
Be able to tune using all of the following ways:
Reference Pitches
Relative to Itself – 5th fret technique
Harmonics
Tuner – tuning app, or one you buy in the store or online that sits by your guitar or clips on.
Tuning Fork
You should understand how each of your guitars need to be compensated when tuning because of their imperfections.
Tuning by Ear – What is meant by this is that from a reference pitch you should be able to tune your guitar just by listening to the open strings without fretting any other notes.

Standard Tuning
Drop D
Eb Tuning – 1/2 step down (1 semitone down)
Drop C

Improvisation
You should be comfortable with improvisation.

Reading
You should know where to find the notes all over the neck of your guitar and be able to read standard notation and tablature.
 

Repertoire
At this point in your study you should have a repertoire big enough that you can play a two hour gig with no problem.
If you are just playing songs then that would be somewhere between 30 and 40 songs. If you are playing classical pieces then this number will be smaller as classical pieces are generally longer in length.