I've been economising for a few years and there isn't much I can cut back on. I did it mainly through 'cutting out the only's'
ie, something you are about to buy that you don't really need or you buy from habit. You tell yourself its 'only a few quid' or that buying things in Sainsbos or Tesco is only a bit dearer than Lidl/Aldi/Market but will take a bit more effort.
I used to multiply the cost of the 'only' by the number of times I might buy it in a year, ie 4 pints milk 20p cheaper at Netto than sainsbos. One of those a day = £70 a year. Only need a few things like that to add up to an awful lot of money each year saved.
I do it with EVERYTHING, food, clothes, toiletries.
I am self employed and would rather spend time shopping round for bargains or visiting more than one supermarket, than work more hours to pay higher prices at Tesco or other such expensive 'one stop convenience' megastores.
Moneysavingexpert has a calculator thing that tells you how many more days/weeks/months you have to work to pay for unecessary repeat purchases.