Don't know much, but there is one thing I do. Like if I want to buy something, I add a certain amount of effort before buying it. Mostly it includes buying gadgets and stuff. Because I love gadgets.
For example, I want to buy an I-pad now. Either I can buy it right now. But this thing gets uncontrolled. So, I buy it after I do certain tasks. Like writing daily for the next 3 months. If I am able to make $100, I will buy a $500 i-pad. It feels really good.
Tried it with iphone, macbook air, acer gaming laptop. Felt better than just buying. Don't know if it counts or not.
RE: Are you able to defer gratification and control urges?