I have been obese for basically my entire life. Last year however, I managed to lose about 25kg (or some 55 lbs for you American folks). That wasn't out of sheer luck, and I have therefore collected the most important points that helped me achieve my goal. First, you need to know your motivation. It might be your health, an event you are working towards, a girl (or guy) you like or whatever else motivates you. Write that motivation down and be as concrete as possible. Now comes the biggest challenge: restricting your food intake or, more specifically, your caloric intake. To do so, it is best to download a tracker like Yazio or MyFitnessPal. For the first two weeks or so, go ahead and track how much you are eating to keep your weight. The average calories are your maintenance calories. From that number, a good amount to subtract are 500 calories per day. This means you will lose around 0.5kg a week as 1kg of fat contains 9000 calories (for body fat it is a little less as it is mixed with other stuff). At first this rate will be faster as you'll also lose lots of water and some muscle mass. Don't worry about your metabolism or a jojo effect as this is a common myth and mainly psychological (dieting at an extremely low caloric intake means you'll burn less calories throughout the day but even then the difference is negligible). Try to be as accurate as possible, weigh your food and register ingredients individually. Eating 500 calories less each day is not easy but there are some things to make this easier. If you eat more fruits and vegetables and drink more water or diet soda you'll be full for far less calories. You might try (or have tried) diets like keto or omad or the many ones out there. These are by no means required for weight loss but if they help you, there is no shame in following them so find what works for you. Doing more also sports helps a lot, especially steady state cardio like walking, jogging or bike riding. Calories you burn doing that translate to calories you can eat. Be cautious though as fitness trackers are pretty inaccurate. To avoid muscle loss, you should also do resistance training on a regular basis. There still is a ton that can still be said so I encourage you to try to educate yourself. However, even if you don't, these steps should help you to become healthier and look better.