HAVE GO TO MEALS
Leading nicely on from batch cooking is to learn how to cook a few go to meals that you always enjoy. It sounds boring to eat similar things regularly but if you enjoy them, it's not at all and it can really help you plan what to buy so that you aren't letting anything go to waste. For me my go to meals are things like casseroles, curries, cottage pies, bolognese - all things that can be made in batches, frozen and I will always enjoy them.
INCREASE THE VEG
Without getting into any ethical arguments around what people should or shouldn't eat, I am currently not vegan or vegetarian but I started reducing how much meat I ate and increasing the veg I ate a few years ago. Since cooking from scratch I've done this even more and it's definitely a money saver, it also allows me to buy the highest possible welfare if I do buy meat, but I actually prefer some of my meat free meals, I think they can be tastier!
Things like veggie curries can be just as tasty as the meat versions, veggie soups are super easy to make and very cheap per portion. Bulking pretty much any recipe out with veg also works to increase the amount of portions at the same time as driving down the cost per potion down.
If you aren't quite ready to go meat free with some of your meals, consider adapting the recipe. Use half as much chicken in your curry as you would usually and add more veg. If making something like bolognese and the recipe calls for 500g of mince, try using 250g of mince and add a can of green lentils. You can do the same with things like cottage pie. It tastes just as lovely, you're still getting protein if that's a concern, but the can of lentils costs probably in the region of 60p, so much chepaer than good quality, high welfare mince. You can also find great meat free versions of classic meals, things like veggie shepherds pie, veggie ragus etc. They are genuinely really tasty and much cheaper to produce.
CONSIDER SHOPPING ONLY ONCE A WEEK
Pre pandemic I used to be one of those people who popped into the supermarket pretty much daily, but over the last year, in part to reduce social contact, I've been shopping just once a week, sometimes once a fortnight and I think this has really helped to save money as first of all I'm using up what I have and making sure I don't waste anything, but I'm also not seduced by offers or things like ready meals after a busy day, so I'm not buying things I don't need.
It does mean you have to think a little more about what you might need to buy, perhaps planning meals for the week, but once you've learnt to cook several meals from scratch this is easier than it might initially seem.
You can also usually look online at what offers are on on produce before you shop so you can utilise that to help you plan around that to potentially save even more.