Dear me. It's been years since I first learned this, and I do love it. It is still part of my routine. In many ways it really isn't as hard as it either looks -- or sounds -- as it contains a lot of repetition.
As I recall, I initially approached the two end sections -- really of the form A1, A2, A1a -- with two different approaches: getting the right hand positions on the keyboard synchronized with the left, as block chords, and then as a separate part of the practicing, getting the cascading arpeggios -- with the same basic hand positions -- going absolutely evenly. Then putting the arpeggios together with the left hand. Then getting the thing up to speed. The two hardest bits, in my experience, were getting the broken arpeggios absolutely even, and bringing out the melodic line (the top of the left hand) clearly and independently.
The B section is really much simpler, but I have two cautions on it: first, do not be tempted to skip the repeats. Play them. Not only do they give you the chance to run through each section twice, but that way you won't have lingering problems with the first endings. Second, the hardest part of the B section is getting the top melody line to sing independently from the underlying chords. Really pay attention to that from the start.
Enjoy!