- Edited
I've been thinking about the video by the pianist that's featured near the start of this thread - what it has, doesn't have, and implied things.
He does RH, then LH, in small chunks and explains why. The music strikes me of having melody (with other voices) in the RH, accompaniment in the LH. Some music doesn't go that way. I see it for this kind.
He seems to "own" theory - i.e. he knows it's in F major, names and recognizes chords. (can't do what he does if you don't have this; but maybe your own associations). He recognizes / hears main patterns like melody and uses that.
Where he plays a small passage with the page open, then covered - then the "forget" by diddling other notes randomly, and back, this makes sense.
At one point he identifies a chord in the RH, says if you include the LH you get a different chord but ignore that; I'm iffy. Supposing your chord (key of F major) is C7b9 - the RH by itself is EGBbDb so Edim7. Is it easier to remember Edim7=>F, or C7b9=>F (the V7 I pattern). But I've done that myself, when the RH chords formed their own pattern if I ignored the real chord(s).
One thing I see missing is looking at the whole piece before starting this. Music has a broad form. Like sonata allegro with theme 1, theme 2, dominant key, back to tonic - Development fiddling with themes - Recap. You have sequences that do the same thing, each time a few notes lower. For memorizing, this is your broad map, like a road trip with broad destinations outlined. Maybe he does this, but it's not mentioned in the video. Or he does a mental perusal which is left out.
Time, stages. Our memory works well when we mindfully go at something; let go; come back to it; let go; come back to it. Some of this would be Mollyish.
One element that we might overlook, is the fact that by looking at small chunks, actively listening, looking for, and feeling patterns in the music, verbalizing them - he is being mindful of what he is doing. If you're a good sight reader, then it's all too easy to let the notes on the page flow into your fingers in a continuum. Did you know you were playing a C7 chord going to F with the 3rd dancing around and resolving to the Tonic note - and relate that to sound, touch, and piano keys?
There are other good suggestions here, esp. the pulling in of other aspects of playing; physical, audial, etc. This thread has been a good reminder of things that I've meant to work on. It's a fantastic thread.
(Edit: Hey cool - this site turns dashes into sophisticated looking bullet points. )