Aspirants can use public speaking to enhance their confidence for UPSC interviews by practicing articulation of ideas and maintaining clear communication. Engaging in activities such as debates or public speaking clubs helps develop their ability to express thoughts effectively under pressure. Furthermore, simulating interview scenarios with friends or mentors can provide constructive feedback, improving both content and delivery. Ultimately, mastering public speaking skills not only boosts confidence but also refines overall presentation skills necessary for the civil services journey.