Drinking water is one of the most beneficial ways to help your body. Not only does it cleanse your body, but it replaces vital fluids that are lost and that your body requires. The human body is mostly made up of fluids and when you lose those fluids (through sweat glands and waste removal) that fluid needs to be replaced. You can get some of that fluid back through the foods you eat (try eating a juicy watermelon, for instance), but you still need to take in clear water to make your body and efficient machine.
Drinking water when you are trying to diet is especially important. Water helps to wash away and cleanse the fat and toxins out of your body. Water also helps you to feel 'fuller' and more satisfied so that you are not apt to eat as much food. When you have a craving, drinking a glass of water can help to curb it.
You should begin each day by drinking at least one glass of water. When you wake up in the morning, go to the bathroom and drink a glass of water before you do anything else. The water helps to get your digestive juices flowing and it lubricates the inside of your body. Drinking water at this stage will help you not eat as much at breakfast as well. Upon waking, your body may crave food because it has been working all night digesting food and using energy to do that. Therefore, you may tend to overeat at breakfast. Drinking a glass of water before you eat can help you with that. You can still have your coffee or tea, but have the water beforehand.
Again, drinking a glass of water before every meal will help you not eat as much. The water tends to fill you up so that you don't have the tendency to overeat. Besides, it has been recommended (and you have probably heard this a thousand times) that you drink at least 8 glasses of water a day. If you have one before every meal, that is half the battle won already.