An investigation of my shopping habits shows that I am a perimeter grocery shopper. What that means is that I shop the food sections around the outside walls of the store the most, eg. meat, produce and dairy. This is healthier eating. The inside aisles are processed foods, of which I buy very little. Coupons are generally on processed foods. Ever seen a cents-off coupon for flank steak or lettuce? I didn't think so.
I also will not drive around to three or four different grocery stores to save a few cents on orange juice and graham crackers because their circular says they're on sale this week. At current gas prices hovering at $4.00/gallon here, driving 5 miles out of my way will cost about 80 cents and that doesn't include the cost of my time spent leafing through circulars, travelling and standing in check out lines. If I see a good sale on something I regularly use at my store, I might buy three or four of them as long as they aren't perishable.
Here is how I save money on food. I look at the sales for the store at which I shop every week. I plan a week's worth of dinners, which eliminates multiple trips to the store (more wasted fuel and time). I try to work in meat, fish and produce that is on sale that week. Generally, we have one night each of fish, chicken, pork, beef, and a homemade pizza night. I'll double the night of whatever meat is on sale to make up seven dinners. I check the cupboards for pantry items that need restocking and add those to list. Finally, I go Coupon Bug to see if there are any coupons that I can use. Occasionally, there are one or two.
About once a quarter, I go to one of those big warehouse clubs and stock up on things we use a lot of: laundry and cleaning supplies, olive oil, trash bags, etc. You can get some great deals, but you have to know prices and stick to a list. I keep a checklist on my computer of my regular warehouse items, so I can go through it before I shop.
Find a system that works for you. It's not the same for everyone. I've got plenty of storage space; you might not. Maybe you are a "coupon goddess". Good for you! If you aren't, explore other ways to save.