Using coupons isn't about changing what you buy but saving on what you normally buy. Sometimes this does mean perhaps changing your brand or being open to different brands but still getting the same basic items.
A great website for walk-throughs is Coupon Mom
Her website is amazing! I use it every week when I do my shopping.
I search coupon deals by state then I click on the store I usually go to. In the list of deals on the left it will tell you what coupon insert and what date it was in the paper. Then you can see the items and if there are any printable coupons there will be a link. On th eright it will show you the price on sale, the coupon amount and the final cost.
Check out her first video on Finding Grocery Deals by State