Make sure you identified the relevant facts. Listen for statements made in class that explain or define the rules in your brief. The note might be a better statement of the rule, or a new rule that has developed since your case. Be harsh on yourself. Do not say, well, that's not quite it, but I was close.
Precision matters in law school.
Listen closely and edit your brief extensively. After discussing a case, your professor may change the facts or present a hypothetical situation - if so you want to write this information down. Hypos are additional examples of how to solve problems using IRAC - when the facts change or when you are given a new set of facts, you need to go through IRAC to solve the problem. Hypos and the reasoning or rationale are examples of the application part of IRAC and you should write these down to study later for the exam. Again, the law school exam does not test you on whether you really remember a case inside and out.