I recently retired, so, am sort of in the same boat! Money is tight. I made a spreadsheet to track my expenses, and it includes columns differentiating between "wants" and "needs." It is interesting to see where money REALLY goes. I break out my "grocery" receipt, with a column for "household needs" such as lightbulbs/laundry detergent, and "personal needs" deodorant/toothpaste; and OTC medicines such as allergy meds and cough syrup. Many times, very little is going for food! I also have a column for eating out, and one for "munchies" (money thrown away in vending machines!) Whenever I come home, the first thing I do is log my expenses. Somehow, just the thought that I am going to have to "report it" makes me think twice about spending it. If you want to go high tech, there are banks that have all kinds of apps for doing this. Unfortunately, I am not familiar with them.
I am not into it, but there are a lot of apps and a lot of coupons. Get familiar with them. And programs that give you cash back, be it a credit card, ebates, etc.
Learn about and create an "emergency fund." It is much cheaper to "borrow" money from your own savings and pay it back, than to pay interest to somebody else, either for a loan or as credit card interest.