The amount of calories you need depends on the activities you do during the day. Losing weight isn't hard, you just need some discipline.
1: Lay off the cola and the unhealthy snacks, but remember to treat yourself every now and again to reward yourself.
2: Don't stop eating. When you ingest too little calories, you're body goes in starvation-mode and you'll stop losing weight. And remember to eat healthy, you need vitamins and fibers as well as fat in a balanced diet.
3: Do some form of physical activity at least 1 hours a day. Doesn't matter wether it's jogging, cycling, tennis or whatever.
4: Don't try to lose weight too fast.
Most important: Don't see it as a diet. A diet ends sometime and you'll regain the weight if you fall back into your old habits. Think of it as a change in life-style.