Learning a new piece of music requires tons of repetition. Sadly there’s just no other way to do it. But there is a basic problem with this. Its repetitive and repetitive! It makes our mind go to sleep, and our brain stop learning. So how can we do the repetitions we need, but not put our brain to sleep? The best way is to change things up when we are practicing.
A particularity easy way is to constantly change the rhythms of the music that we are practicing. By changing only the rhythms you are repeatedly playing the same notes, with the same fingers, but providing just enough variety to keep the brain engaged. The easiest way to do this is to alternate long and short notes, sort of like a dotted rhythm. You can do it with a long/short pattern, or with a short/long pattern.
I have found just making this change can hugely reduce the time taken to learn a hard passage of music, and it seems to make the music sink in more deeply. I always practice difficult passages using this technique before a performance, it seems to hugely reduce the chance of me playing wrong notes. It’s kind of amazing, its the easiest practice technique I know of, but by far the most fruitful.
Try multiple ways of varying the rhythm. There can be different degrees of dotting, from triplets all the way to double-dotting. Try patterns such as one note long followed by three notes fast. Try any pattern that fits the musical passage that you are working on. Your practice sessions will become shorter, more efficient, and more effective.