When you learn a piece, practice each note in a piece of music separately, every trill and embellishment. All tones that are supposed to sound must be included. Make sure that every tone gets an open, sonorous sound, equal to the typical demand of a choir director or classical singing teacher. This is possible with instruments and singing alike.
To achieve this you can imagine a tube coming up from the ground, between your legs, where the sound comes up and out into the air. Each tone will usually have to be played several times, until it has a sound that is pretty neutral and unformed, but open and in full voice.
You do this with no real consciousness about style, phrasing or technique, you just treat every tone as a separate thing. In the end the whole piece lies around you in pieces, like an unfinished jigsaw puzzle. In your mind, of course.
When this work is done you leave the piece until the day after, and then go on practising the way that suits you best. What you achieve is access to your own sound material, combined with the music you are dealing with. You can use it for any purpose, for doing whatever work you do to make the music sound good.
When you get as as far as public performance, the piece also sound better and is more easily available for interpretative improvisation. I feel also that it influences the technical side of playing in a good way, making the muscles more supple.
This work may be viewed as «research», in the sense that you establish the basic facts – the tones – that your piece is made from. The interpretation can then be given the structure or the shape you want, according to style, personal taste and musical architecture etc.
The method is not recommended when working with jazz or so-called rhythmical genres, because you get to the point the wrong way. It works for music where sound is the focal or main point of the music – classical music and maybe some popular genres.
This work should ideally be done when you start practising a piece.
It may also be used for warming up, in which case you use few notes, on the piano 5-finger position, until you feel fit to play or practise. Hit each key with a finger, then relax without removing the hand, then hit another key with another finger, and so on. Do this really slow. Change fingers sometimes systematically, sometimes random, to make the whole hand supple. The relaxing effect may also transform itself to arms and back. Once in a while make sure that your sitting or standing position is ok too.