My method is a very slow one, but it is good, I think. First, I study the struture of the music and how it develops from the theme: inversions, mirror, retrogrades, tonality changes, etc... I do this away from the piano. When I have understood all this, I use "mental playing", visualizing in my mind the sheetmusic and each key. Then, I practice HS only one bar or one musical phrase, a lot of times. Doing this, I say the name of each note (or sing the name). After this, I study the next bar, allways repeating it a lot of times and saying or singing each note. Then, I play the two bars a lot of times, in the same way... The same with each one of the other bars. So, when I finished a section, I have repeated the first bar for example 50 times, the second 49, the third 48 and so on. Allways with the name of each key. So, after this, I`m able to wright from memory all the sheat music, without any mistake. Mental memory, fingers mechanical memory, visual memory, structural memory... But my work isnt finished yet. I go to the use of the pedals, the dinamycs, etc. When all is done, I play daily this music at least five times, along a month or even more. And I only know that I have the piece studied when I can play it "saying" it from my heart and my mind, without any technical dificulty. When I was 15 years old, I have study the 12 variations of Mozart "Ah, vous dirai-je maman". With 30 years old, I went to Angola where I coudnt play piano along 5 years. When I returned to Portugal, I could play them without any mistake, and without the sheet music, only by memory. Thats why I have a lot of pieces I can play easily, by memory.