Start small.
Get a notebook (small enough to keep in a purse or pocket) and write down EVERY SINGLE EXPENSE.
I do mean everything, to the penny. If you spend 20 cents on a stick of gum, write it down.
After keeping track of your expenses in this way for a couple of weeks, you will begin to identify patterns.
Perhaps you habitually stop for a cup of coffee whenever you drop your clothes at the cleaners, or maybe you stop for ice cream whenever you take the kids to the park.
Impulse buys and 'little treats' will show up when written down like this. Once you can identify those purchases, you may be able to cut some of them out - and put the money you save (by not buying said items) into the bank or an investment account of some type.
Before too long, you'll be surprised at how much extra cash you have.