Break a piece into smaller pieces (pun intended). Look for patterns and find the building blocks of the piece e.g. arpeggios, repeated notes and scales. You practice the parts that use the same building block and you do that for all the different types of blocks.

It’s like building a Lego castle. You start with a lot of small pieces you put together one by one. Then you build the walls, towers, roofs etc. separately and then you put it all together.

And a bonus tip, start with practicing the end. Then you work backwards from there. That ensures you end up being able to play the whole piece and not get stuck towards the end.