Have a plan
You need to start off with a plan. Perhaps each day you will find one thing that you spend money on and see whether you can reduce how much you spend on it. This can be anything from rent or mortgage to utilities from food to financial products. If you take a look at everything that you regularly spend money on, you may find ways to reduce the prices with a small amount of effort but not noticeable long term effect apart from having more money.
Gather the paperwork
You will need to get together you bank and credit card statements to find out what you spend money on. If you spend a lot of cash, then these purchases will be less clear so you need to start noting them and writing them down. You could put together a list of items that you will tackle each day. It is wise to start off with the really high expenses and then work through to the cheaper things.
See it as a fun challenge
You could set yourself it as a monthly challenge; maybe note your progress on a social media account. Each day list the item that you are going to try to reduce the cost of and work hard to do so. You should find that it becomes enjoyable and you may find that friends and family ill want to join in.
You may still be unsure of where to start, but it is pretty easy. Take your water bill, think about if you are metered and whether you could save water anywhere, perhaps by using devices in shower heads or loos to reduce water use or flushing less often, fixing dripping taps etc. Then you could concentrate on electricity, see if you can swap to a cheaper supplier and switch more things off to save how much you use. You could make your own packed lunch instead of buying one, source cheaper food products, cut down on how much alcohol you drink etc. Each day note down what you tried and how much you saved and at the end of the month you should find that you have a significant amount built up that you will be able to start saving if you wish, using to pay off debts or spending on treats for yourself. You will find that they more you do it the easier it is and you may want to work at it more and more.