What helped me was cutting out soda and coffee from my diet.

It sounds like exercising more often would be a good solution. Working out once or twice a week will not provide very good results. Short workouts three or more times a week will yield better results than an intense workout once a week. It's also best to spread the workouts out a little bit rather than working out three days in a row and then not for four days.

ETA: Snacking is good!! If you snack a little bit on healthy stuff and therefore eat less at mealtime it can also make a difference. You can also write down everything you eat during the day to make yourself more conscious of what you are eating.