How do you eat less? How do you eat/manage less calories when you are used to eating lots every meals?

All my (25f) life I've been skinny and people (moreover my parents) praise me when I eat a lot when I was a kid. We also grew up kinda poor so we always have to finish what's in our plate. I grew up loving All-You-Can-Eat buffets and people compliment me how I am so skinny but eat so much. It was viewed really cute when skinny girls eat a lot and don't gain weight in Asian countries. So in my head, its cute, its normal, I'm fine and I don't need to change anything. Also during my teenage years even if I stuff my self full, after the next day, the stomach bulge is gone. Now it looks like it's here to stay if I don't do anything. And I realize I have to change before it gets really out of control. So for anyone like me who didn't get the good discipline in eating, how did you overcome overstuffing yourself? How do you eat less even when you still don't feel full?