We had to cut back a lot on maternity leave and then just kept up with the money saving tips once I went back to work. Things that have really helped us are:
Eating mostly vegetarian. Beans and pulses are far cheaper than meat. If I buy meat it's when it's on a yellow sticker price at the supermarket and I put it in the freezer.
Having two or three days a week when we eat very cheap meals. Tonight it's beans and fried egg on toast but it could just as easily be jacket potatoes, or soup and baguette, or pasta and pesto.
Buying cheap fruit and veg. Fresh we tend to buy apples, pears, plums, bananas, onions, carrots, leeks, potatoes etc. Anything else I buy frozen e.g. frozen berries are a fraction of the price of fresh and work well in porridge. Or I buy frozen broccoli and cook it in the same pan as cooking my pasta etc.
Baking our own snacks. I can make a tin full of simple biscuits for about £1.
Eating out less and if we do it's getting coffee and a cake out rather than a full meal. We went out for brunch as a treat at the weekend and it cost £50 for the four of us. That's easily a week's worth of dinners so it's something we do very rarely.
Not buying fabric softener. I just stopped purchasing it a few years ago and it's been absolutely fine!
Bar soap rather than shower gel. It lasts longer, is way cheaper and actually makes me feel cleaner.
I make my own cleaning sprays and just reuse old cleaning bottles. Lemon juice or white vinegar, a squirt of washing up liquid, tsp of bicarb and topped up with water. If you want it to smell nice you can add a few drops of essential oil but I find if I use lemon juice rather than vinegar I don't need the essential oil. I stopped buying special floor cleaning solution and just add a capful of disinfectant like zoflora or the B&M cheap version to water and mop with that.
Buying clothes on vinted but in general, buying far less stuff.
Free activities at the weekends. We like geocaching, which is completely free. Or visiting museums, or going to the library and each choosing a new book, or going on a walk and taking a picnic.
We got rid of Sky TV and just bought a Freeview box. It's been absolutely fine.