A simple tip: just make sure you don't have enough cash to spend on those impulse purchases.

How to do this? Whenever you get paid (salaries or whatever) just add most of the money on a savings account. Make this an automated process. Just keep enough available for two weeks of groceries and whatever else. Halfway of the month, add some cash back from the savings account to your regular account to last for another two weeks. Make this an automated process too.

So, what's going to stop you from plundering your own savings account for a big shopping spree? Hopefully, that would be laziness plus the extra delay that it would take for the transaction from the savings account to your regular account.

Finally, make sure your regular account doesn't allow you any credit. It should not allow you to go into the negative numbers.

A few simple (but not easy) tips:

1. Have a written budget that includes a 'blow money' category.
2. Spend every dollar on paper on purpuse.
3. Withdraw that 'blow money' category money in cash

Use cash for those impulse purchases. This will do 2 things:

1. Psychologically, the 'pain receptors' are activated in the brain when you use cash. This will discourage you from frivolous spending. It will literally 'hurt' a little
2. You can't spend more than you have if you have cash. But you'll be more inclined to bargain or find a deal (and this is good).

My personal preference is to avoid malls and shopping altogether :) But if you HAVE to go to a shop, make sure you always have a list and don't buy anything that's not on the list.

I also find that after I got my finances in order and figured out what's really important I always have a monologue running through my head asking me why I'm buying something and whether it's something I really need. If the answer is yes I buy it, if it's no I put it back and move on.

Maybe you can create a similar script that you'll remember when you're buying something you're not sure of.