Aspirants can effectively take notes for UPSC preparation by implementing methods such as the Cornell note-taking system or mind mapping. Highlighting key points, summarizing information in their own words, and organizing content thematically enhances retention and understanding. Using bullet points for clarity and incorporating diagrams can further aid memory recall. Regularly revisiting and revising these notes will reinforce learning, helping candidates stay aligned with the extensive syllabus. Also, digital tools like apps can be utilized for efficient organization and accessibility.