To keep a Christmas tree fresh and healthy, it's important to provide it with the right amount of water. A fresh-cut tree needs water daily to stay hydrated, while a potted tree can be watered every few days. Make sure to check the water level in the base regularly, and keep the tree away from direct sunlight and heat sources. Additionally, adding a fresh cut to the base of the tree each time you water it can help it absorb water more easily. Finally, keep your tree away from any fire hazards and make sure to properly decorate it to avoid any accidents.