@ho not sure who it was but I read about a hiphop producer who had a technique for "fresh ears". They had a loop that went like this:
- listen to the track and take notes
- work on the changes they wrote down without listening to the full track
- stand up and walk away for a long time, do something else, go for a walk, etc.
- repeat
The key being you always hear the track as fresh as possible for that first task of taking notes.