Then, use it at the store. Keep a running grocery list in a handy spot in the kitchen, such as the refrigerator door, for family members to write down things as they use them up. The list is at least partially ready to go with the first person who volunteers to do the shopping. You don't have to use up brain power trying to recall that you're almost out of Cascade and cottage cheese. You can concentrate on a weekly menu instead.
Some people find they are less distracted if they make their list correspond to store aisles.
Count the numbers. Jot a quick note. Try to plan at least one thing for each dinner. The fish, the most perishable item, is cooked first. Or, a menu plan could revolve around cooking techniques.