The guitar may be played in all keys, but it has some keys more favorable to it than others.1
Most used major keys in the guitar: C, G and F.
Most used major and minor keys: D, Dm, A, Am, E an Em.
These keys are more popular in the guitar because they require the usage of the Barrer less often.
It is important, however, to be acquainted with all the keys.
To facilitate the execution of the scales, it is necessary that the fingers of the left hand should be placed sufficiently separated that they may be put on and taken off the strings, without moving the hand 2
When passing from one note to another, the finger must not be raised too quickly from the string so they can vibrate well.
New and Improved Method for the Guitar, by Matteo Carcassi, Boston : Oliver Ditson & Co, 1853, p. 21. Archive.org, archive.org/details/newimprovedmeth00carc/. ↩︎
New and Improved Method for the Guitar, by Matteo Carcassi, Boston : Oliver Ditson & Co, 1853, p. 22. Archive.org, archive.org/details/newimprovedmeth00carc/. ↩︎