I've heard a lot of things like chewing your food 15 times will help you lose weight or having a glass of water before each meal will help you eat less. How do I know what is true and what isn't? – Breara*
Chewing your food 15 times can slow you down if you're a fast eater and allow you to enjoy your food. Any slowing-down technique can help you avoid overeating and better pick up on your body's cues that you're full. Drinking water before you eat probably won't make you any more full, but it won't hurt, either. But eating food with a higher water content, like fruits, vegetables, and even soups, will make you feel more full, so you eat fewer calories.
If you're looking for specific advice on nutrition or weight it's best to ask either your doctor or a registered dietician. But if you find yourself searching for answers online, always use reputable sites. When hunting for info, use common sense — if certain advice seems too good to be true, it probably is.