The first step is to make sure your tree is fresh when you bring it home. Make sure to check for any signs of drying out or shedding needles. Once you've got a fresh tree, you can keep it that way by keeping it well-watered and away from direct heat sources like radiators or fireplaces. If the air is dry, consider using a humidifier to help keep the tree hydrated. Finally, try to decorate your tree with ornaments and lights in a way that allows air to circulate around it.