Write down total (honest) income and outgoings. I go through my online banking. Go back about 3 months to make sure you have all spending.
Make a budget. Include savings to cover emergency/surprise spending.
Meal plan
Put cash spending in different envelopes or in different bank accounts and transfer correct amount in at the start of the month.
Leave your purse/bag at home as much as possible. Decide to have 1 spending day a week where you make all purchases. Anything forgotten waits until the next week. Unless it's essential.
Switch down brands in the supermarket. Try and make a note of the prices on things you buy regularly. Check stores like poundstretcher, B&M, Poundland etc for the same items but cheaper.
Check direct debits and see if any can be cut completely or reduced.
Set budgets for Xmas, Easter, birthday spending.
Start Xmas shopping early. Use eBay, charity shops, buy and sell pages on FB.
Walk instead of driving/bus as much as possible.