Sometimes the best food buys I get are buying bulk staples like peanut butter, flour, rice, beans, coffee, sugar, tea, meats, spices - all at stores like Sam’s or Costco - then I take portions of each and lay them in freezer bags and keep them in storage for future meals.
Buying fresh vegetables for the week on a saturday and keeping them in the crisper bin of the refrigerator helps keep down the everyday gas mileage to get to the store and back. If you have a yard suitable for growing a garden, you can cut some corners buy growing what you may want to eat on your own.
I changed all the light bulbs in my house to the lowest wattage/ highest lumens allowed for each socket, and keep the air conditioner/heater on a constant 70 degrees. (In Texas, it helps tremendously with the power bills)
Do showers instead of baths. Wash all laundry on Saturday, combining as many loads as your washer allows - using the coldest water setting, and the least-heat for the dryer (or string up the washing like I tend to do outside when the weather is nice)
Learn to sew! You’ll be able to help keep clothing in good use by repairing when need be, and you can also stitch up pillow cases, sheets, blankets - the works.
Find garage sales in the area to go to on the early weekends, you can grab cheap dishes, cheap books, cheap everyhting if they are smart sellers. Keep an eye in your local paper for advertisments of certain items you’re in need ot, like a new table or a bed - everything goes with a garage sale!
Start a “household” money jar. Get a large jar (I use a large washed out 2 gallon pickle jar) and start saving any and all change that passes your hands. Pennies and nickels add up! My parents bought their entire brand new bedroom suite in the 70’s (500$) all with the loose change they saved up for two years.
If you’re buying bottled water at all, switch to buying a filtration system (20-100$) and cleaning out the tap water.
If you both drive, try to plan trips together. Carpool when possible.
If either of you smoke or drink alcohol, give it up for a tremendous increase in savings. Helped me out big time.
I am so longwinded.

I hope some of this helps!