Good way to save money

So I've been recording our expenses and have been appalled at some of our spending esspecially when I talk to some of my siblings and they live off 1/3 or less of what I've been spending on groceries and such. Soooo, I haven't spent hardly anything this month, and my seceret? Don't shop and when I do it has been for exactly what we need like 2 gallons of milk and a carton of eggs and just using what I have around the house. Of course this will backfire when I've depleted every thing we have at home, but it is a good idea for this month since we'll be going on a trip soon and I can leave our fridge empty.