How can I keep my expenses under control?

I am a 27-year-old bank employee. I find myself consistently spending my entire salary each month. Along with a monthly rent of ₹15,000 for my PG accommodation, I also allocate a significant portion of my earnings towards eating out, travelling, movies, and other leisure activities. As of now, I have no dependents. How can I keep track of and control my monthly expenses so that I can start saving and make investments?

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