Case note is different to an essay. You have to get to grips with the actual case IN DETAIL.
First thing is. Print the case out. Read it multiple times. Do not reply on textbooks for explanations.
My approach to a case analysis would be:
Intro (10% word count)
Identify and state the MATERIAL facts of the case (5%)
Identify and state the legal issue(s) the court had to decide AND if relevant the procedural history i.e. what did the lower courts decide (10%)
State clearly and precisely how the court arrived at their decision (20%)
Critical analysis: what does this case add to this area of law? Is it a good decision. If not, why not? How are you defining good? How do other jurisdictions deal with the issue raised by the case? What do academic say about the case? DO you agree? (55%).
Conclusion (5% word count)
Pvt message me if you need anything clarified.