1) Consignment sales. Selling and buying there. Check out Bargain Watcher to find consignment sales in your area. Also if you can tell your friends and family that you are selling stuff to bring in extra income you would be surprised at how much you will get, trust me. You can even turn yard sale-ing into an Ebay biz. I thoroughly enjoyed Yard Sale Mommy. She stopped posting last year but she was very descriptive on what sells and how to sell it well. Worth a read.
2) Aldi, is my favorite store, you can find less processed foods for the same price you get at the stores with a sale and a coupon. Build a price list of all the things you buy on a regular basis and figure out the lowest price per ounce/pd/unit and aim for that. I buy german coffee, oats, tuna, tortillas, butter, sour cream, eggs, milk, canned tomatoes, cheese, bananas, frozen chicken breasts and frozen vegetables.
3) Consolidating trips. Less gas, less wear on the car, etc. Avoid running to store for that one thing. When you go to the store ask your neighbors if they need anything. And maybe they will start returning the favor.