Diet & exercise. Make sure you exercise at least 30 minutes a day, don't skip meals, avoid soda, juice, dairy, alcohol and fried foods. Eat a healthy well balanced diet! Also water, organic vegetable broth, green leafy vegetables, natural pickles, apples are great to fill you up so you dont feel hungry and they are very low in calories.
Portion control. The key to a good weight loss program is portion control with appropriate balance of carbohydrates and proteins. 5-6 small meals a day instead of one large meal. Commercially available programs like medifast and optifast can make it easier to start but you should eventually transition to wholes foods.
Addressing specifics. Each person a program that works with their lifestyle and health issues.