Write down all your expenses for a month.
You will experience that it's a bit of an eye opener, when you note all your expenses, big and small ones, over a longer period of time. 30 days as a minimum will give you a detailed insight into your spendings. Save all your receipts and make a list of all your shopping and expenses at least once a day during the 30 days.
Keep in mind that nothing should be left out: Food and groceries, toiletries, takeaway coffee, restaurant visits, clothing, the hairdressers, cinema tickets, school supplies, women's magazines.
After a while, you will be able to spot, where your money is spent every month. Maybe you'll even discover specific areas that you wish to change, things you could easily live without other you would like to prioritize.