Utilise olio and/or yellow sticker food. I havent bought bread/rolls or the kids weekend pastries in months. This does breakfasts and lunches for free.
When cooking meals make an extra or 2 for the freezer. Eg curry, Bolognase, dahl, chilli, soup. Then when you have a can't be bothered to cook night you can get leftovers out. We have freezer pot luck at least once a month.
Meal prep on days off - I chop all fresh ingredients on Sundays and Wednesdays. That means in the morning I just chuck it in the slow cooker and dinners ready when we all get home.
Plan easy or treat meals once a week. This will reduce the temptation for takeaways. Better to pre-empt it as it will be far cheaper than the takeaway.
Look at all bills, what is really necessary. We rotate tv streaming services and only have 2 max at a time. I buy dvds in charity shops (10 for £1) or carboots.
Sim only will always be cheaper for mobile phones, I put money into savings for if we need to replace a handset. (Never more than £200 on music magpie for a decent one, if that lasts 2 years that's still only £8.30 a month, less if it lasts longer) our sim only is £5 a month for 10GB data plus unlimited calls/texts on o2. I used uswitch to compare and switch. For an equivalent contract including a phone I would be looking at £30+
Sell old items/clothes on vinted before buying new. I also look there first before buying new. In my toughest times money wise I would buy from charity shops and sell on for more. In my mind I gave them the asking price and I could then sell to buy what I needed.
Days out look for cheap or free offers. Especially if you are on low income lots of places offer discount for universal credit. Alternatively if travelling by train lots of 2 for 1 deals available. With some research and time exciting days out are within reach for all families. Book train fare in advance, I recently did a return to London with my daughter for £12 instead of the usual £27. We took a packed lunch, saw the sights and went to a free museum.
Be open and honest with friends about whether you can afford it. If you can't afford drinks and dinner out, they could come to you, or go for lunch, go for a picnic. Find a restaurant that let's you bring your own drinks (several now popped up near me) They may appreciate your honesty and just aren't brave enough to say it.
Most importantly work out your priorities and cut back accordingly to afford them. For us our priorities are having experiences and days out. So we don't drink (except rare nights outs), food is on a super tight budget (vegetarian, no processed snacks), no expensive make up/toiletries etc. Our food/cat/toiletries/household cleaning budget is £300 a month for 2 adults, 2 teens and 2 cats. We eat well with occasional treats. We don't drive, walk as much as possible and get public transport if its more than a 45 min/1hr walk.