I suggest putting your food on a small bowl or plate. That way, you still get to munch, but you can't over do it. With a whole bag of chips in hand, it's SO easy to eat the whole gosh darned bag--but when you have a limit in front of you, you're more aware of what you're eating, and how much.
If you like snacking all day, try finding things to snack on that are low or no
calories. Butter free popcorn is a good choice, or carrot sticks, some fruits and berries... You have lots of options! Again though, put what you eat on bowls or plates, so you know how much you're eating, and so you don't eat yourself out of house and hold (: It's helped me to count things out, and only eat a serving size of what I crave, while putting the rest away and out of sight.