Aspirants can articulate their thoughts clearly during the UPSC interview by practicing mock interviews and self-reflection. They should focus on structuring their responses logically, employing frameworks like the STAR method (Situation, Task, Action, Result) to clarify their points. Listening carefully to the questions is essential, ensuring answers stay relevant and concise. Moreover, practicing public speaking helps instill confidence, enabling candidates to communicate their ideas effectively while maintaining composure under pressure. Regular engagement in discussions and debates can also improve fluency and clarity in expressing thoughts.