I am not an expert in IR neither did I ever studied social sciences before. But here is a tip:

Critical analysis is actually effect of a particular event (as mentioned in the question) on overall world scenario (or on a specific country if mentioned). So, while attempting a question would include:

1. Background of the event i.e what, when, how, who (who means who is/are the major actors in that specific event).

2. Causes of the event (if you think they are prerequisite for the next section)

3. Effects of that event (on the region or a system whatever specified)

4. Conclusion

Type of effects are usually mentioned in the question.

For example in 2017 IR part I, there was a question:

"The nation-state system is in a flux with an independence referendum in Scotland and another projected for Catalonia in September 2017. Critically evaluate reasons as to why the modern nation-state in Europe faces internal challenges to its sovereignty and territorial integrity."

Soultion:

1. Background: You will throw some light on what, when and who of Scotland and Catalonia Referendums.

2. Causes: You will discuss why they are happening?

3. Effects: In this case, the effects are on a system (Nation-State of EU). So you will take every element of nation-state one by one and discuss if that element is being hurt due to these events. For example, nation-state has 4 basic elements i.e Sovereignty, territorial integrity, legal equality and nationalism. But if you see closely, examiner has already lighten your burden by specifying those elements at the end of question: Sovereignty and territorial integrity.

Conclusion: In this part, you will just summarize your critical analysis (part-3) in a few sentences without going into factual details.

Just note down this pattern and apply it on any question. I bet you will thanks me a million Good luck