In tune with last week's tip...try to only buy what you need (or at least what you went to the store for).
How many of us run into the grocery store for a gallon milk (strategically placed in the back) and come out with two bags full of cookies, ice cream, and chips?
So for those quick, pick-up trips to the store:
First, NEVER go to the grocery store hungry....EVER!
Secondly, make a list (at least in your head).
Third, pick up a basket, canvas bag, or grab a large box from the produce shelves. NO CART.
This will limit the items you pick up since you have to use your arm strength to carry them through the store...especially if milk, juice, or laundry detergent is on the list.