I always make a list when doing my "big shop," but since I tend to shop at the same store, I created a permanent list in Excel. The list follows the layout of the store. I can then print the list and fill in how many of an item I need, or simply put a check mark. Then I cross items off as I shop.
I always have my lunch packed, clothes ready, and put my bag (complete with keys, wallet and phone) in the same place every night before going to bed. No wasting time in the morning looking for things.