The article Supermarket Smarts by Consumer Reports discusses ways to save at the grocery store. One way to save up to 51% on your grocery bill is to pass up the pre cut and pre sliced products (such as vegetables, cheese, bagels, etc). A rule from Stephanie Nelson, The Coupon Mom is that if you can do a task in less than 5 minutes it’s not worth paying for convenience packaging. Another example is to buy a bigger bag of snacks, chips, etc and divvy into smaller snack size bags instead of buying the prepackaged snack size items. I know it may seem handy to purchase these items but if you look at how much more you pay for a few minutes of work, it may deter some purchases of the pre packaged items.
Also, watching for items on sale. Sale cycles seem to run about 12 weeks. If you see an item you use regularly on sale, try to buy enough to last a few months. A few dollars may not seem like a lot here and there, but it does add up over time.
Shop with a list. If you have a menu plan for the week and make a list of items you need.
Like other habits you are learning, it takes time and discipline. Small steps will get you closer to your goal.