The main identity of a classical guitar is that it is played typically by plucking. However, some modern classical guitarists have come up with new techniques that also involve the use of a 'plectrum' while plucking or strumming.
Classical Guitar Techniques
Typically, a classical guitar has smooth nylon strings, which are very soft to play, and their sound is soothing to the ears. They create a sound which is totally different from the sound generated by plucking or strumming normal steel strings. If a player is acquainted with a classical guitar, he can create new techniques and produce different sounds.
Mastering classical guitar techniques certainly needs a lot of practice, and includes a coordinated use of both hands for playing effectively. The tone quality and difference primarily depends on the way the player uses his right hand to pluck or strum.
The tuning of a classical guitar strongly depends on individual preferences. One can use the normal tuning pattern like 'E A D G B e' or the D drop tuning style 'D A D G B e'. The player can even tune the guitar in ways that are comfortable with the positions of his fingers on the fretboard.
This is how new chords and playing techniques develop in classical guitarists. The right plucking hand is very important for the sound that has to be generated with a particular rhythm style.
Plucking is a technique which has been widely used by classical guitarists. It involves the use of individual fingers on different strings. This technique enables the player to produce smooth sounds which are generated by the touch of the fingertips, unlike in the case of plectrum's tip.
In plucking, the thumb is generally placed on the 'E' or 'A' string, and gives the hand a steadiness in playing. It is also used to pluck the 'E' or 'A' string, when an appropriate bass sound is needed.
The pointing finger is supposed to be used to pluck the 'D' string, middle finger for plucking the 'G' string, the 'B' string is plucked by the ring finger, and the 1st string that is 'e', is plucked by the little finger. The plucking of all these strings is done in an accord with the appropriate rhythm.
The earlier mentioned manner of plucking is mostly used by classical guitarists. However, there are some guitarists who may not be comfortable with this plucking style, and may use a different style according to their convenience.
Sometimes, only the treble strings of the guitar have to be played for a 'twin lead' or 'seconds'. In such a case, the guitarist may use the thumb and pointing finger to pluck the treble strings. However, there is no hard and fast rule that a particular finger needs to be used only on a specific string.
Another classical guitar technique is slapping all strings or some of them on the fretboard, using the pointing finger. This technique is useful in producing smooth chord sounds along with a little touch of 'harmonics'. A technique much evolved nowadays among classical guitarists is the incorporation of a drum-like instrument within the body of the guitar.
The guitarist plays the normal guitar along with the rhythm, which is given by his plucking/ strumming hand on the drum-like instrument. The plucking or strumming and the drum instrument's rhythm have to be in one accord.
There are many more classical guitar techniques, which can only be learned after some professional guitar lessons and thorough practice on the guitar. One may never know, if he would come up with a technique which is not even known to professional guitarists.