Coordinate sales with coupons. For example a store by me has Juicy Juice on sale for $2 a bottle. I have coupons for .50 off one. If your store doubles you get them for $1 bottle (they usually run about $3.50). Fortunately my store triples up to .50 so I got them for .50 a bottle.
Purchase the smallest size you can with your coupons. Usually you can get a lot of things free this way.
Look into rebates, too. You can often get free things this way. You have to pay first, but can get it back. Often times you can actually get paid for a refund. If you combine a sale, coupon, and refund, you often make money on the deal.
If you go to
http://www.valupage.com
you can purchase certain items and recieve a coupon off groceries on your next trip.
Your biggest expenses will be meats and fruits/veges. If you go to a store on Monday mornings, you can often find meat marked down. Freeze it and you will be fine!!!
Often times, you will also get a "catalina" which is a coupon that the computer prints out when you buy certain things. You can use a manufacturers coupon in addition to these. Also, store coupons can be used in conjunction with manufacterers coupons.
If you are able to combine all these.....sales, coupons, valupage, rebates, and catalina coupons, you will be able to save anywhere from 50% to 110% easily!!