A pound of fat equals 3500 calories. To lose 1 pound a week you will need to expend 3500 more calories than you eat that week, whether through increased activity or decreased eating or both. Losing 1-2 pounds of fat a week is a sensible goal, and so you will want to use the combination of increased activity and eating less that will total 3500 calories for 7 days.
Although exercising is great just being more active is also a good way to burn calories. There are many small changes you can make to your daily routine that will burn calories for example: