Drink more water. Adult humans should drink a liter or more water per day. That is in addition to things like tea and coffee. Water keeps bodies at the correct temperature and removes toxins that are the inevitable result of metabolism and industrial life. You'll be healthier automatically.
Water also clears your skin, helps your kidneys, helps to control your appetite, and keeps you energized.[1] If being healthier, more wakeful, and having better skin isn't motivation, what is?
In addition, it keeps you from drinking unhealthy beverages like soda and juice, which are high in calories. The body barely registers the intake of these unhealthy drinks and yet you still feel thirsty hundreds of calories later. If you need the taste, splash some lemon, lime, or 100% juice into your water. However, be sure that you are drinking a sufficient amount of milk to maintain the strength of your bones into old age.