Move more, eat less.
Portion control counts for a lot, not many use it, do you need that heaping spoonful when a level spoonful will do? Read the nutritional labels on the package, pay attention to the portion size for the numbers quoted, companies play with the numbers by adjusting the portion size so that it sounds better than it is. Don't feel like because you have large plate you need to fill it with food, use a smaller plate and it looks fuller. Theres lots of mind tricks you can pick up with the psychology of eating.
Just because you're watching what you eat doesn't mean you have to deprive yourself of the things you enjoy, thats why most diets fail. Don't "diet", most see that as a means to a goal, you need to fundamentally change how you look at eating and make a lifestyle change, diets are doomed to fail because they're temporary . If you feel like you're giving something up, as diets tend to do, you feel like you're missing out and fail, make the choice to eat better and you'll miss nothing.
Avoiding fast food altogether is the single best thing you can do for yourself, nothing like getting a whole days worth of calories in one meal.
Don't under estimate the power of walking every day, and I mean not just a walk, pick up the pace and get your heart beating for at least 30 minutes, and even pick up the pace walking out to the car in the morning. Park out in the boonies at the mall, avoid the idiots and pick up the pace going in.