Your first weeks weight loss is as much due to losing your store of glycogen as it is to do with losing the fat. We should normally carry a store of glycogen that accounts for about 2 to 3lb of weight, but when you restrict your calorie intake your body uses up the glycogen as well a losing the fat store, so your first weeks weight loss will be higher than any other week because of that. After that your body will readily shed some fat, but then that slows down as your body starts to adjust to the lower intake.
There is nothing you can do about it, its just the way the body works. You will find that after a few weeks weight loss will level out to 2 or 3 lbs a week. People get discouraged when their weight loss starts off really well, then levels out to this level, but losing 2 or 3lb a week is an excellent loss, especially once you have got to week 4 and beyond.
There will be times when your body stubbornly refuses to shift any weight for a week or maybe 2 weeks. This is another breaking point for many as they feel whats the point of eating so little and not losing anything, but again its just the bodys way of adjusting and the weight will start moving down again.
Its worth bearing in mind that once you come off a diet, or ease up, your weight will stall or increase by a few lbs as the first thing your body does with any excess calories is to put that store of glycogen back asap.