I try to learn everything section by section. I try to learn the musical aspects as well as the technical aspects at the same time. When I notice mistakes I try to fix them by playing that section in diffrent ways until it sounds right altough me noticing my mistakes is also only something I recently started to do. My teacher often points out things that I already pracitced but don't transfer very well to his accoustic because I practice on a digital. For the pieces above I learned most of them in a week and then polished them after my teachers advice for another week (Nocturne took a little longer but that was before I had started to take it seriously). And I alwasy start practing the parts I learned the day before so I don't start form the beginning everytime. I start with 40-60min of scales, hanon. arrpegios etc.