Although individual playing styles and hand positions will vary tremendously from one player to another, essentially there are two basic techniques which can be used when it comes to plucking a string with the fingers. Generally these can be considered to be either with or without preparation, and depending upon which type of stroke is used, a different sound and tone can be achieved. The idea of plucking a string either without preparation, or with some form of preparation, can be applied to a wide range of playing styles and sounds.
For example, by playing a note without preparation the fingers continue with the plucking of strings uninterrupted, and this means that either a full flight or speed stroke is achieved. This is often identified with the tremolo effect. However, the idea of playing a note either with or without preparation should not be confused with the idea of either a rest stroke or a free stroke. The rest stroke and free stroke techniques can both be introduced regardless of whether preparation is used or not.
So what is meant by preparation in any case? Sometimes the term preparation is replaced with the term planting, and this technique involves putting the soft part of the finger, and possibly even a small portion of the nail, onto the string itself before the note is played. Once a small portion of the finger is already on the string, it is then plucked. This all happens in a fraction of a second, and is considered the normal way in which a string is plucked.
By using this standard way of plucking a string, music can be played at anywhere from a slow to a medium pace perfectly adequately. Because a very fine combination of nail and finger is used it often helps to make sure that the nails are cut carefully and kept in a good condition, and if using a guitar which does not have nylon strings, and instead has metal strings, such as steel, then this technique may well need to be adjusted.
This technique has a great advantage as far as beginners are concerned because it allows the player to obtain a much better feel for where the individual strings of the guitar are, although there are some music teachers who recommend against this method being used for the purpose of getting used to the position of strings.
By playing a note or plucking a string without preparation, no part of the finger touches the string before the note is plucked. Instead the nail catches the string in full flight and plucks the string as a single manoeuvre. This is often used for tremolo effects where a string has already been plucked, and it still in the act of vibrating. The full flight method of playing can pluck the string again, and by not using any preparation the same note continues as the string continues to vibrate. For very quick scales and riffs this method of playing can be very effective, although it is also essential that the left hand is equally fast at managing to press the correct frets at the same speed.