Techniques to develop a coherent narrative in essays for UPSC involve outlining main arguments, structuring paragraphs logically, and using clear transitions between points. Starting with an engaging introduction can capture interest, while a strong thesis statement sets the tone for the argument. Each paragraph should focus on a single idea that relates back to the thesis, reinforcing the narrative. Concluding by summarizing key points and reiterating the main argument helps to leave a lasting impression. This structured approach ensures clarity, making essays more persuasive and impactful.