Drinking more than two liters of water a day
Drinking two liters of water a day is important indeed. However, you can also overdo it. A glass of water before eating reduces appetite, so you eat less. Do not think two glasses of water is a good substitute for an entire meal. The appetite comes back later and the chances of you having a bad snack will improve!
You might have a weakness for chocolate ice cream or pasta with extra cheese. The best things are often also the things that contain the most calories. Of course you will lose weight by avoiding this food, but because of tthat you'll only crave it more in the end. It is best to eat everything in moderation! Too much of anything is never good for you.
Dedicating too much time to sports
Working out is, of course, the best way to get in shape, but the mental aspect is actually much more important because when you only focus on sports, chances are that your social life is less present, and, as a result, you will quickly start to feel more lonely. Loneliness is a major cause of feeling bad. Consider what you find most important: a killer body or a good and healthy social life.
Eating less than 1200 calories per day
Everyone's daily calorie needs and are different. This will depend on your height and weight. Yet, everyone is advised not to consume less than 1,200 calories per day, as the body turns into 'survival mode' when you do, which will slow down your progress.
Weighing yourself multiple times a day
Your actual weight is not always a good indicator to measure whether you are successful at dieting. They are just numbers, which can fluctuate enormously during the day. You will make yourself crazy by checking the scale daily. Weighing yourself once a week is more than enough. Focus on other signs of success as your energy levels and feeling better in general.
For a healthy, responsible way to diet, you can ask it best to seek help of a doctor or dietitian.