SOTW Columnist, Distinguished SOTW Member
Repetition is the key. You have to play it over and over until it is fully internalized. And, most important of all, get away from the written page asap. I've found it almost impossible to memorize a piece of music by simply reading it; best to learn it by ear or read it only briefly, then continue working on it by ear. This may not be true for everyone, but I think it is for most. Probably because as long as you are reading the notes, you are relying on a visual cue, a 'crutch' so to speak, and it doesn't get fully internalized in your ear/mind. That's my hypothesis anyway, and I'm sticking to it.It has always been difficult for me to learn music by heart
p.s. Just realized I said something similar earlier in this thread over a year ago...but it still stands.