1. Stop buying stuff you don't need
You don't need it. Trust us, you don't.
Just because it's on sale, doesn't mean you have to buy it. In fact, just because it's free, doesn't mean you have to take it.
Your grandmother's aunt's sister's cousin's brother-in-law's nephew's nephew's nephew's nephew's cousin's brother-in-law's wife's sister's cousin's brother-in-law's nephew's brother-in-law's brother-in-law's brother-in-law... didn't buy it, and they're doing just fine.