Chopin etude No. 1, with fingerings for the left hand and exercises
My piano philosophy
You should always play from memory. Playing from sheet music is as if you proposed to someone and read it from a piece of paper.
I will never be able to play the piano with my hands as Sviatoslav Richter did with his hands but why shouldn't I be able to play in my head like Sviatoslav Richter? Practise your repertoire also in your head until you can at least play in your head like some famous pianist.
Your fingers can be faster than your head, thanks to their reflexes, but the reflexes may deteriorate. Is it you that's playing the piece or are your reflexes playing it?
Don't play as fast as possible. Rather play a bit slower but with as much control as possible.
Practising too intensively can damage your hands, and practising a piece for months or even years can spoil the piece. A hundred repetitions in three weeks are more effective than a hundred repetitions in one day.
From my experience, it's a good rhythm of practice to alternately practise a piece for some weeks and then let it rest for some months. Thus, you can repeat many pieces often enough, the pieces can develop and there's enough time left to learn new pieces.
New pieces must be practised more, of course, but not a hundred times in a row. Practise new pieces alternately with pieces that you already know, for example like this: new piece, old piece 1, old piece 1, new piece, old piece 2, old piece 2, new piece, old piece 3, old piece 3, new piece etc.
The next piano lesson is no reason to practise only for it all week.
Weeks or months without learning anything new are wasted time that you can't get back.
Forgetting something because you didn't repeat it in time, is wasted time that you can't get back.
(But if you're sure that you don't like a piece any more, then you shouldn't play it any more. So think about it, before you start learning a new piece, if you will still like it in 10 or 20 years.)
Piano playing should of course be brilliant and expressive, but above all, it should be simple, true and natural, with as little ego as possible.
Expression is not something you can put into a piece of music, but every piece of music has its own expression, and you have to discover and to recreate it.
Thinking has to do with awareness and music has to do with awareness but music has little to do with thinking. You can't explain music but you can become more and more aware of what's happening in the music and how everything fits together in the best possible way.
You don't play the piano in order to get points for following the composer's or your teacher's instructions. Your mistakes have to bother you, and you should play as it seems right to you. Not because you know better but because your awareness is the only one you have.
Everything has to be as big, as strong, as fast, as loud as possible today. Most pianos are too loud, not really made for small rooms and "chamber" music.
Music doesn't just start with a cut and eventually end with a cut, but every piece of music comes from silence and returns to silence when it's time.
Don't just play "the piano"; don't play for a big audience; play "für Elise" and be happy : )