We recently put a new grocery shopping strategy into practice. I sat down and planned out seven days of meals, wrote up an ingredients list, and only bought exactly what we need to make it through a week.
I think I can safely call this the single biggest change we've made to reduce our spending and food waste. I've bought groceries for less than $40 for three weeks running now. This past week, because we're shopping light on the promise of Thanksgiving leftovers, we got our week's worth of groceries for a whopping $28, and all the food we bought was fresh and unprocessed. I feel pretty good about it.
I was amazed to realize how much food we were buying that was simply extra. We ate most of it, but a fair amount was getting thrown away, because it was being bought without a real plan.
I definitely recommend giving this method a try if you don't do it already. You might be surprised.