Assess everything on a “$1 per use” basis.
I have my mother to thank for this one. Everything I buy — clothes, shoes, household items — is assessed on the basis of, “Will I wear/use this enough to only cost me $1 per wear/use?” Now, obviously, things like wedding dresses, for example, don’t fall into this category. But, next time you go to buy that trendy, ephemeral “must have” item, break its cost down into realistic uses. Often, you’ll find that what seemed like a deal is actually a waste of money, and, it will find its way to the back of your closet after a few brief wears.