A more subtle one. Get a bunch of bag clips (I used IKEA ones) then write the name of all the things you keep in the freezer (peas, sweetcorn, chips etc). You want 2 of each. Attach 1 to each bag in the freezer, open or closed. You also want a piece of string attached somewhere. When a bag is empty, put its clip on the string. Congratulations, you now have a shopping list. Once you restock, just attach the clips to the appropriate bags, before putting them away.
At least for my household, this seems to flow well. There are no hard steps, and an obvious flow to it. Unfortunately, I've yet to figure out how to extend it to canned food, but it works for any bagged foods (pasta etc)