My main tip is meal planning, so you just buy the groceries you need. If you have space in your garden get a raised bed to plant veggies. Onions are so hard wearing, by Autumn after they've dried you have enough onions till spring. You can buy salad leaves to plant in a few tubs that regrow. A bag of posh salad leaves is at least £1! Try and make as much at home you can. Depending on whether finances allow, join Costco as you can get stuff in bulk for cheap saving money. We bought a huge tub of ketchup & carex for example and just refill empties. Use shops like home bargains, b&m etc for some of your branded items, although you can't really go wrong with Tesco's basics in everything, especially fruit & veg. You're eating it not taking it on a date.
If you can afford too, do your shopping online, that way you don't get tempted by stuff you don't need. Evening delivery slots are £2, minimum order is £40, but we do a monthly shop for jars & tins etc. Rather than brands look to their own brands. Buy fruit & veg in person as you can pick what looks like the best.
Try and tailor meals that can be used the next day. So any left overs could be your/hubbies/DC's lunch. Be more creative with what you cook, so sausages, Tesco's own are the same as Richmonds, not the basics, their normal. You can make, try and eek things out.
If you don't bank with Halifax they give you a reward for joining, if 2 Direct Debits go out & £750 goes in a month, you don't pay charges for their reward account. That gives you phone insurance, travel insurance, breakdown cover and something else. So you save on insurances. Your whole family is covered on holiday insurance, it's a nice extra to have for saying we won't be in the EU so the EH1C card may be dormant.
So get 1 bank account, pay everything into the account and your bills out of it, then you can use the other accounts to have your own money for the month. Get a spreadsheet & work out what you spend.
If you get CTC you can get £140 added to gas account, so that ASAP if you haven't. If it's one of them dongle things they add it into that. Make sure if you pay monthly you're getting best deal on gas & electric. If you have Sky evaluate what you need, even though the thought of losing sports might kill your DP, if you ask to take it off they might do you a deal. Same with broadband, get the best deal. Phone contracts, if they're up for renewal consider going PAYG, I think it's Three where you get unlimited data, 200 minutes, 2000 texts plus 'Free to Three' calls, so if you & hubby on same provider you can call him for free. But don't go for deals where you're effectively paying monthly for a jazzy phone. Do you need the latest phone or can you make do with what you've got. There's sites which tell you where the best deals are.
Aldi is really good for booze that is less than £5 but the same as brand names. So avoid paying crazy money for branded wine, spirits & beer. Although for beer you can get deals at certain times 3 packs for £20. Look online for what premium brand tastes like an economy brand. With bread Tesco's do loaves for 50p you don't need the branded stuff. Things like pasta, rice, could cous, can be bought in bulk from Costco for a fraction of the price. Find out when supermarkets reduce foods, Monday's after 5/6pm is the best day for cheese & other bits from Tesco's. You can freeze cheese & quite a bit. So you could get reduced loaves, baps, crumpets, cakes & freeze them to defrost when you need them. It might mean having 2 freezers but it'll pay for itself. You can go to local butchers & see what they do in meat packs, that way you can get a months worth of meat for £20. Use 1 pack of mince or 1 chicken breast when cooking, you don't need to go OTT using all 4. Bag and freeze. The same with sausages, bacon etc, split into portions & freeze. Aldi is great for chocolate & cereals. But own brand cereals are fine.
If you have lots of spare time consider couponing, but only get stuff you'll use. Shampoo & conditioner, again home brands, shower gel, whatever is on offer. Tesco's razor is the same as the Mach 3 by Gillete but so much cheaper on blades. Sanitary wear, again if possible own brand, I find Tesco's 19p towels better than Always plastic ones. But it depends how heavy you are. But tampons are pretty much all the same. Kitchenrolls own brand, tissues the basics, toilet roll I think is 9 rolls for £4.
Buy what you need not what you want.
Clothes, evaluate do you need a new outfit or can you jazz up what you have. Primark is good for vest tops & short sleeve tops. Don't be tempted by sales, it's usually old stock. For your wardrobe consider staple items you need. Look around charity shops on a day off alone, gauge which is the cheapest. Then set up a wardrobe with staples of certain clothes, then you can mix & match. Sainsburys do decent men's t-shirts & kids clothes as do Primark for men's & girls stuff.
For birthdays buy the cheaper cards in Card Factory, for kids parties the 10 for £1 ones are good enough. Post Christmas try and get next years cards and wrapping paper. For Christmas don't blow yourself crazy, buy things the DC's need as stocking fillers. Search through charity shops for quirky gifts. Books go pretty cheap and most aren't even read. Try and limit what you spend on each DC. They're not going to be traumatised if they don't have a mountain of presents. Buy for Xmas & Birthdays what they want within reason, not a million things they'll never touch. Same in charity shops or fairs like school fairs / charity fairs, you can pick up unused stuff. If you have friends with older kids, see if they have spare costumes you can borrow.
You should try and put some money aside for savings. It's better to pay with cash than struggling with credit. This goes for electrical stuff, Even the next family car.
Make sure you get all money you are entitled to. Savings you may as well put in Post Office bonds as you have a chance of winning with them and your money is safe.
Depending on how much you earn, you should look to have as much spare as you can, for holidays, birthdays, Christmas, electronic failures like a new Hoover or washing machine.
We are a family of 4, including mortgage, ctax, bills, food, it's roughly under £1000 a month. I think even £800! So it can be done.
The main thing is ok your fridge won't look like an advert for a chain supermarket but you'll have the food you need. All the ingredients for Shepherds pie can make 2/3 adult meals and then 3 frozen children's meals. I don't think I said, it's tempting to buy ready meals, or stuff from the canteen but you'll save so much doing it yourself.
Hope this helps