A common weight loss technique is "thinking yourself thin". While I'm not a fan of the wording, I do believe that the ideas behind this method of thinking do make a difference if you're trying to lose a few pounds.
Out of sight, out of mind...
...if you clean out your kitchen of unhealthy foods then you won't be tempted to reach into the cupboard and start snacking unhealthily
...slowly sip on water throughout the time between meals to curb "hunger" pains (chances are you're simply thirsty)
...however if you do become hungry don't ignore what your body is telling you
...it's important to eat healthy snacks and to not starve your body if it's telling you it's hungry
Take a walk...
...a lot of snacking comes from being bored
...when you have nothing to do and feel the need to go grab a snack try going for a walk instead
Don't fill up 100%...
...take slow, small bites and avoid eating while distracted (don't watch TV or surf the net)
...if you're consciously aware when eating you'll be able to tell when you start to fill up (whereas if you're distracted you'll generally continue eating until you're finished what's on the plate in front of you)
...after eating healthy for a period of time it's important to reward yourself for treating your body kindly
...something like after two weeks of no junk food you can buy a new item of clothing you've been wanting is a great motivational tool to encourage your mind to treat your body well
It's important to not take these ideas too seriously. Don't think that when you do actually start to feel hungry that water will fill you up or that you can't eat because it's not lunch time yet. It's important to listen to your body and if it does start to tell you it's needing fuel that you don't ignore those requests (just be sure that you go for the healthy snacks instead of the chips or cookies).