One thing that can make you spend way more money than you should is impulse buying. Impulse buying is unplanned buying that you decide on the spot when you find something interesting. This is dangerous for your personal finance because you can easily spend a lot of money this way.
A good way to fight impulse buying is by creating a shopping list before you go shopping. List everything you need at home before you go to the grocery store. Then, when you’re there, just find and buy all the things in your shopping list and nothing else. Since you already have a list at your hand, it will be much easier to get rid of impulse buying. When you find something interesting, you know that it’s not in your list and therefore you shouldn’t buy it.
Of course, for it to be effective you need to be discipline to stick with your shopping list. Don’t forget to strictly follow your list. What if you find something interesting while you’re at the grocery store? Well, just write it down for your next visit’s shopping list. There’s a good chance that later you will realize that item is actually not necessary.
On the other hand, if you go shopping without a shopping list, you risk buying a lot of unnecessary stuff. This is something you definitely need to avoid.