Ok, so, we’ve diagnosed the problem: learning a piece by starting from the beginning is not necessarily a good idea. The progress is slow, the feeling is not satisfying, the going is tough.
But, you might intervene, there are no other ways to go about it! We have to be a slave to the timeline, and the timeline is always going from beginning to the end. We are pushed toward the future. There are no “buts” or “ifs” about it.
Very well. Since we are talking here in a friendly way, I shall accept the challenge.
First of: never mind the timeline. The brain we have can do all sorts of things to the timeline. Timeline are not the subject here. The task at hand is though! The task! The piece! The work to be done! That’s what’s on the line here!
Now, is there a single good method. Watch for my answer, you’re ready?! Pay attention, I don’t want to repeat myself. NO! is the answer. No, there is not any single method. There are many of them that can be tried.
For example, you can try doing a road map. A road map is when you look at the piece in its entirety BEFORE you actually put your hands on the instrument. You go slowly with the road map. It’s really important not to miss anything. You determine the different parts, the difficult passages, the repeat signs, the articulations, the dynamics, the sticking or the fingering, where the phrases are going to breathe, where the rhythm will be tricky, etc… In one word, you make sure you understand what you’re up against.
Then you start the piece from the beginning and, if you mess up, you go back to the beginning, then if you mess up, you go back to the beginning.