how to distinguish obita from ratioWatch
In terms of a staged approach, I would take it like this. Firstly, what are the facts of the case? Second, what question(s) is the court being asked which arises out of those facts? Thirdly, what parts of the judgment deal with answering that question as it applies to those facts? All that is part of the ratio. Then fourthly, what am I left with? Generally that stuff will be obiter.
A word of caution on this. Sometimes, particularly in the higher courts, decisions will be made on broader matters of principle which are more loosely connected to facts of the specific case in hand. Equally, and again in the higher courts, cases will often be joined, so the question the court will need to answer will be more general. In those circumstances, the facts of each underlying case may be less relevant. But you still need to go through the process of working out what question the court needs to answer, and the parts of the judgment that go to answering that question.