resisting tempation to stupid things you dont need.
and eating out less(home usually food, somewhere). driving slower(saves gas $).

setting a weekly budget, and trying to stick with it. the rest goes towards whatever goal i have/timeframe for something i want to buy. or into savings.

i carry little or no cash, i can look in online banking to see where my money goes and to who.

those simple rules are quite effective for me.