I'd look at - swapping dome fresh fruit for veg, which is often cheaper. Frozen fruit, tinned and dried too. Only eating 1 or 2 expensive fruits a week, the rest get apples, oranges etc that are cheaper.
I'd also look at buying double 1 week, making for 4 and freezing half. Generally buying larger packs and cooking once is cheaper.
Use everything up once a month, so you have a 'no spend' week.
Try not to have massively different meals, so you don't need to buy loads if different ingredients.
Buy things that go a long way. For example ... Greek yogurt can be used for breakfast, making naan breads, tzatiki, in curry, as a marinade. I buy things with lots of flavour, jars of sundried tomatoes, parmesan etc so a little makes a big impact.
Learn to love scraps and use everything up. Soup,.salad,veg curries. Find Accounts that use kitchen 'waste' on Instagram, I follow one called.scrappy cooking, or similar.
Save any spare portions in the freezer for pitta/wrap night. Add salad, cheese, dips or sauces.
Obviously pulses are your friend. As are the fresh fruit and veg offers, frozen veg too.
Remember a jacket potato, or beans on toast, are a meal.