Make a master grocery-shopping list.
Organize the items you buy regularly in the same order they are located in the store. Leave some open lines between each category so you can list additional items where they belong.
Make lots of copies and always keep one on the fridge.
This will take you an initial investment of time, but will save you SO much time when you go to the store that it will all be worth it. Trust me.
My mom did this when we were kids. And my mom is simply awesome. So there you have it. :)