To make a Christmas tree last longer, there are a few steps you can take. First, make sure you choose the right kind of tree. A fir tree is a good choice because it has a natural resistance to drying out. Second, make sure you cut off a few inches of the trunk before you put it in the stand, this will help it absorb water more easily. Third, make sure you keep the tree well-watered, and keep the water level topped off in the stand. Finally, keep the tree away from heat sources and drafts.