Effective note-taking during UPSC preparation involves techniques like the Cornell method or concept mapping, which help in organizing information logically. Candidates should focus on summarizing key concepts, dates, and definitions in their own words to enhance retention. Using bullet points and highlighting important terms can also aid in quick revisions. Furthermore, integrating visual aids like diagrams or charts may boost comprehension and memory recall. Regularly reviewing notes and incorporating insights from current affairs can reinforce understanding and keep the information fresh during preparations.