I always left ethics for the last two weeks. The way I saw it, if I studied it early I would forget it anyway come the finals weeks. At least this way it’s still fresh in your head since you first learned it.
read the CFAI ethics chapter the week b4 the exam and do all the EOC questions
I used broadly the same strategy for ethics for L1 and L2. ie CFAI text and a lot of question practice.
Do all the ethics item set questions you can get your hands on. the item set format makes the questions a bit tougher for ethics in my opinion.
I would also recommend spending a bit of extra time on Soft Dollar and Research Objectivity. I was constantly tripping up on these questions in the build up to the exam so I ended up writing out all the details (ie required and recommended) for both on 1 page a few times and it seemed to make the penny drop.
Having said that. I walked out of the exam thinking that I’d definitely nailed ethics and it ended up being my only section under 70%. just 2 questions max from a clean sweep, damn you ethics!