You can lose weight by eating less (smaller portions is key), eating healthier, and drinking a lot of water. Green tea is also very healthy and promotes weight loss. Avoid drinking diet drinks like soda, because that will really not do anything to help you reduce your weight.
The first thing is cut sugar and junk food and make sure you eat healthy foods and in small quantities. Try and move from time to time because it will help in the digestion of food. Make sure you are doing a little exercise. It will speed up the process of losing weight.