Hi there, Brain storming could be easy once you are well versed in overall skeleton of you task 2 .
The typical essay structure is ;
1. Introduction Paragraph: (Max 60 Words)
-Paraphrase Question
-Develop thesis Statement (Your Opinion)
-Background Information (To simply mention what you are going to discuss in next 2 Paragraphs)
2-Body Paragraph 1: (Max 70 Words/5-6 Lines)
-Main statement related to topic and coherent with background information in first Paragraph.
-Real World Example or case study Example of situation/problem under argument.
-Cause and possible consequences.
-Solution to discussed problem.
3-Body paragraph 2: (Same as Previous Paragraph with different content
)
Max 70 Words/5-6 Lines)
-Main statement related to topic and coherent with background information in first Paragraph.
-Real World Example or case study Example of situation/problem under argument.
-Cause and possible consequences.
-Solution to discussed problem.
Conclusion
Max 40 Words)
Conclusion of Body Paragraphs 1 and 2.
Overall Opinion (Should be very clear)
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If you have above structure in mind, you need brain storming for 2nd and 3rd paragraphs only and for rest your writing needs to be organized and coherent.
Brainstorming Technique: Visualize yourself in that situation and take deep insight for possible pros and cons, merits and demerits and so on as per essay topic and try to think more realistically which could be your or some one's personal experience OR even from content of any TV program/News/Movie or story narrated by your colleague!
Hope that helps but Practice is the KEY to success in IELTS! Best of Luck .