Have you got any receipts to look through?
I have found it useful to break down receipts to look at where the money is going.
Things like nice shampoo/ conditioner plus a bit of makeup can add to the bill.
How much is cleaning products/ household/ toilet paper etc?
How much is luxuries like wine/ beer/ snacks/ chocolates?
How much meat?
How much fruit/ veg?
How much is processed/ ready meals?
How much is store cupboard staples?
Next I tend to look at favourite family meals and price them. For example we used to like fajitas quite often. I'd buy chicken breast, a fajita kit, guacamole, sour cream, grated cheese, bag lettuce, tomatoes, onions, wedges. As a meal it worked out more per head than steak and chips. I'd rather steak and chips and mentally I thought of it as a cheap midweek meal, it wasn't.
Pesto and pasta is something we also enjoy, quick and easy and very low cost per head.
Reducing the overall shopping bill can be helped by planning your meals, as everyone has suggested, but also costing them so you have a balance.