Participate in a No-Spend Month
Redditor acts541 gives the lowdown on how you can start a no-spend month: "Pay all the bills at the beginning of the month, set aside your 15 percent savings (or more), and only spend money on gasoline & groceries. That means no eating out, no alcohol, no renting movies, no shopping, etc."
This plan enabled him and his wife to become debt-free in three years with six months' worth of savings. They would participate in a no-spend month every other month. If this sounds too extreme, you can always tweak it to suit your lifestyle, for example, having a no-spend month once a year or a no-spend week every month.