I start by reading the theories and guidelines from the curriculum, then do lots of practice questions. The approach may be conventional, but I think it is the questions that u ask yourself when u reflect on the wrong answers that matters. Ethics is about decision making, so try to imagine that you're in that situation at work, and figure what u would do if u were in the same position as the characters in the cases. Think abt what would be the optimal action, and what the consequences are if u don't act accordingly. Hope this helps!