Starting out, it was not eating after 8. That's when I snacked the most so I just marked it off there. I lost like 15lbs doing just that. Since then, I'm with Pammy on portion control.
Planning, like others said. But to change it up a bit, I also think that it's important not to be too strict because for me, that can lead to a binge or several weeks off plan.
1. Never eat unless i'm hungry.
2. Only eat enough to not be hungry.
3. Do not eat food other people have prepared. Needless to say I absolutely refuse to eat out, and only eat what I bring to parties and stuff, but I was like that long before I started dieting due to the fact that I think everyone is gross and I don't want them touching or breathing near what i'm about to put in my mouth.