There is not much I can do to stop spending because I don’t really ever buy anything. If I got into a bad habit of spending money on random little things I would give myself a budget; a percentage of what must be saved and what I get to spend on little things. I would make the amount of what I spend on random things smaller little by little.
If you live at home, use that to your advantage. You don’t need to buy a little bit of food here and there for yourself just because you want it. It is the same for apps and in app purchases. You may really want to get ahead in a game so you buy five dollars worth of in game money, but working for it will always be more satisfactory. And it saves that money for a time when you really need it.
Let’s say I had a job and a person gave me a tip, I would only spend the tips and not the pay-check (unless it was being a waiter, because most of their money comes from tips).
You have to prioritize on what you spend. You have to spend money on food, but you don’t have to abuse it. Don’t buy all the food/toys items that you see on the way to the cashier — you don’t actually need any of those things!
I don’t really ever spend much, and I am doing my best to keep it that way.