1.Food that is in easy access will always be eaten no matter what time and what instance. For example do not place a place a jar of your fav candy within reach at your desk, you will just be consuming the candy the entire day. Instead put it in your drawer to decrease the chances you will dig in but to really decrease your chances of consuming the junk keep it far enough away way you have to stand up and walk to get it. To try to limit the amount of food you eat don't leave so much on your desk. That means no "stocking up."
2.Fast Food joints are guilty of this one. Bigger portions in bigger plates mean bigger consumption. If your plate is full of foods that are delish to you the chances that you will consume many calories and saturated fat in minutes are great. The large burger, fries and soda offered for very little money at your local fast food joint are made with ingredients that are unknown. That's a scary thought. Your body isn't a trash can so don't put in crap. Just because food is cheap doesn't mean you have to order mass quantities or at all.
3. I'm guilty of this one as I'm sure you are too-eating while working, studying, or watching TV. You are distracted so it's difficult to notice the amount of food you are eating. Within minutes you can consume something that would have taken you hours. I know you know this but I am going to say it again... Eat a satisfying meal full of fiber and vegetables plus a little protein and little fat before you sit down to watch the new fall TV shows. Your stomach will be full and you will be less likely to dig into the bag of oreos.