Losing weight isn't about silly ideas or having it fall off fast. You probably didn't gain it fast, so you can't expect to lose it fast either. 15 lbs is too much to expect to lose safely in one month, but you can get started and lose as much as possible.
The 3 areas that are the most important for weight loss, seem to be the 3 areas in which you're the least flexible. Those are diet, exercise and sleep.