What I do is I just take the money I need so I have a limit. It also works if you use cash instead of credit or debi card. Cos with card you could go over the limit you've wanted and its so easy to just spend it cos you actually dont see how much your spending while your trying to add everything you've been buying in your head. With cash in your hands you see how much money gets out of your pockets and you resist the temptation of handing those money and buying something than using a card.
Thats what I do when I go out. Or what I also do is just be focused on what you really need, for example try and save up for something that you really want which will be impossible for you to get and when you see pretty things around you'll be thinking you need to save t up for something and also if you dont really need it for anything, just say that to yourself quietly or in your head.
Hope that works for you :)
Tell yourself to think of all the reasons how the thing your about to get would help you, and if they all sound dumb - dont get it!
Don't take your wallet, checkbook or charge card when you go shopping. Take just the amount you will need.
just spend all of your money, then you can't buy anything. problem solved
Lol :) good one