Most people eat more than they realize, most of them even eat when they're not realizing it (snack while watching a movie) and keeping a food diary gives you an insight what you really eat. Write down every meal you had and how much (use your hands as a measuring guide), write down every candy, cookie, fries you ate ... Write down even how much water you had that day, write down every beverage you consumed, along with every sugar cube ;).
It may sound pathetic but sometimes such little things can sabotage your progress and you may ask yourself why you don't see any progress (progress can be loosing kilograms, centimeters, to fit better in clothes, feel better, get a better health ...). Little cheat meal every day may not sound a lot, but eating something "bad" every day is worse than eating one cheat meal per week. Reserve one day to have a cheat meal, it may be a birthday party, going to a cinema and having a popcorn, having a pizza date ... Other days eat clean and healthy.
I hope you find this tip helpful :)
Do you keep a food diary?