Certain areas of the grocery store should be seen as having treats that should be occasional purchases and not routine ones - your bags of cookies and chips, tubs of ice cream, etc.  Only walk down these aisles if you are satisfied with the progress of your diet changes and it's been a while since you had those treats.  A good way to prevent yourself from buying these things every time is to only get your favorite flavor and only when it is on sale.  Look at that $5.99 tub of ice cream and say, "Nah, it's not worth it.  In a few weeks, it'll be $2.50."  Then wait the few weeks.  Maybe at that point, you will not even be craving it anymore.