Before writing essays for the UPSC exam, effective brainstorming techniques include using mind maps to organize thoughts visually. Starting with a central idea and branching out can spark new connections. Additionally, using the free writing technique allows for stream-of-consciousness writing to gather ideas without judgment. Creating a structured outline helps in organizing arguments logically. Engaging with peers in discussions can also generate varied perspectives on a topic. Lastly, identifying key themes related to current affairs or subjects in the syllabus can guide focused brainstorming sessions to produce compelling essays.