Change your diet.
No more than 1500 calories per day.
exercise regularly (3-5 times/week)
Much of over eating is our tendency to use food to solve our problems (a way to seek comfort, fight boredom, dull ourselves so we don't feel as anxious/depressed, for entertainment, etc.). Food is nutrition and if we use it for more than that I think we're guaranteed to overeat. (the solution is to find alternatives other than food, to satisfy these needs and urges)
My suggestion is: eat healthy food choices at meal times in a quiet, pleasant setting (not while watching TV) until you're no longer hungry, and avoid the practice of eating until your feel 'full' (as that's usually too much). Have healthy snacks at hand (carrot sticks, apples, etc.) if you need to snack between meals. You might try camomille tea if you're feeling especially anxious (rather than resorting to an extra bit at meal times or snacks).
What do you have for breakfast? I'm an advocate of a hearty breakfast (it really sets the day off right, and avoids blood sugar levels plummeting which would challenge any dieter to stay the course later in the day and evening). Oatmeal porridge is an excellent component of a hearty breakfast.