Scan the sale paper prior to going to the grocery store rather than browsing through it at the store. This way you know what sale items you need.
Create a list of all items that you need, including sale items. If you know your grocery store well enough, create the list in the order that you will pass that item in the grocery store. For example, if the produce department comes first and the meat department next, write the list: strawberries, lemons, and onions; ground beef, fish and beef cubes.
Clip and sort all coupons prior to going to the store. Attach the coupons to your list with a paperclip so you can easily glance through them at the store. Note next to each item on your list if you have a coupon and what the details are. If you have a coupon for canned soup, note that on the list and include "$1 off the purchase of four cans." This way you don't have to stop and go through your coupon for the details. You can just glance at your list.
Shop the store according to the order of your list and make one rotation around the perimeter of the store, then cover each aisle where an item is needed. Do not aisle hop from one end of the grocery store to another and then back it again. It wastes time and increases the chances of adding things that you don't need to your cart.
Place orders for all items that you will need to wait for first, then go grocery shopping. For example, if you need prescriptions and deli items, drop off your doctor's script to the pharmacy and then go to the deli and place an order using the computerized system if it has one. This way, supermarket employees will be working on your orders while you shop so you don't have to stand around waiting for them to fill your requests.