Trim The Trunk
When you get your tree home, make a fresh one-inch cut off the end of the trunk and place the tree in a bucket of warm water until you put it up. This cut eliminates any dried-over resin that blocks the tree from absorbing water.
Place your tree in a sturdy stand that holds at least one gallon of water. Fill the stand with one quart of water for every inch of trunk diameter.
Place Your Tree Away from Heat Sources
A decorated tree beside a fireplace is beautiful, but if you use your fireplace regularly, it contributes to your tree drying out more quickly. If your home is prone to dryness, try running a humidifier.
Keep Water Level Above Base of Trunk.
Too little water causes resin to form over the cut end of the trunk. Once that happens, the tree stops absorbing water and dries out quickly. Water additives, like bleach, aspirin, and sugar, won't hurt, but most experts agree that plenty of plain water is all you really need to keep your tree fresh.