Make a fresh cut to remove about a 1/2-inch thick disk of wood from the base of the trunk before putting the tree in the stand. Make the cut perpendicular to the stem axis. Don't cut the trunk at an angle, or into a v-shape, which makes it far more difficult to hold the tree in the stand and also reduces the amount of water available to the tree. By sawing off the base, you will open up the pores, and the tree will be able to absorb water.
To display the trees indoors, use a stand with an adequate water holding capacity for the tree. As a general rule, stands should provide 1 quart of water per inch of stem diameter. Devices are available that help maintain a constant water level in the stand. Watering is critical. A freshly-cut tree can consume a gallon of water in 24 hours!
Never let the water level go below the tree's base.
Keep trees away from major sources of heat (fireplaces, heaters, heat vents, direct sunlight). Lowering the room temperature will slow the drying process, resulting in less water consumption each day.
The best way to avoid a mess removing your tree is to place a plastic tree bag (available at hardware stores) underneath the stand when you set the tree up. You can hide it with a tree skirt. Then, when the holidays are done, pull the bag up around the tree, stand and all, and carry it outside. Obviously, you will want to remove the stand before recycling the tree. If some needles do scatter inside, it is better to sweep them up; as needles can clog vacuum cleaners.