Keep your potted Christmas tree moist but not overly wet. Using a saucer under the tree will catch any excess water and provide a small amount of water for the tree to use between watering.
Try to limit the time the tree is kept inside, just a few weeks would be fine. When it is time to take it outside, slowly introduce it to the sun. A few days in the morning sun and then slowly into the full sun. This will help stop the tree from getting sun burnt.
Use Seasol as a gentle liquid feed to help the tree get over the stress of being inside. Repot if needed into a slightly larger pot with Brookfield Potting Mix. Potted trees will need to be kept moist throughout the year. Fertilise four times a year with a slow release fertiliser and you will have a beautiful tree for next year.