Here is how I plan my shopping trips!
I review the store's weekly ad to see what's on sale and match-up coupons.  Then I take advantage of the money-makers, freebies, and cheapies!  For the rest of my groceries, I buy just the essentials for the week - and I look for coupons for those, too!  Then I make my list and I take only the coupons that I plan on using.  I also make a back-up list, in case some things are out of stock and I still have to meet a purchase requirement.  If I see a good deal but I don't have the coupons I need, I will note the sale and return at a later time.  While in the store, I pick up the popular items first, and then the remaining items.  I always make sure the product matches the coupon, and that the product is indeed on sale.  Before I go to the register, I double-check my coupons to make sure I got everything.  I want the check-out process to go as smoothly as possible!  I hand over my coupons in a single stack and then watch the register closely as each one is scanned, reducing my total one by one.  I always use reusable bags and then I push my cart full of groceries out the door!