You know what I do when I learn a new piece? sort of dumb, but it works for me. I take the bingo numbers (in italy, from 1 - 90)- I divide the piece into small 3 or 4 measure "phrases". It depends on the piece, but a musical phrase usually covers 3 or 4 measures. In a piece like the liszt sonata, I would first divide it into 4 main groups, then subdivide it. Stick to one group which is more or less like a movement from a sonata. Subdivide it. It might come to about 40 subgroups. Then I put the numbers in a bag and take one at random. I learn that little group, by memory. But it includes everything-musical AND technical things. And I learn it by memory hands separately, as well. If I know the piece - "know" in the sense that I've heard it lots - I might be able to do 3 or 4 groups a day.
I do this little game because my concentration powers are not all that great. If I start a piece from the beginning, in a normal start to finish procedure, I sort of get lost and don't really finish a small 3 or 4 measure group. I also find that if I don't commit it to memory immediately, it takes longer to learn it. Because I'm not really "trying" if I use the music.
But these are MY quirks!