They should be supple and springy to the touch. Bounce the butt of the tree on the ground to see if any needles drop. If more than a few needles drop, the tree is not fresh. The sap on the tree stump should be sticky and moist, not hard or caked. Also choose a tree with an attractive color and a full, bushy appearance.
Most people prefer a conical, symmetrical shape to their tree.
The branches should be sturdy enough to hold ornaments and other decorations such as small gifts. An alternative to the cut tree is a live tree that can be obtained at nurseries and tree farms. After the holiday season is over the containerized tree can be planted in your yard. Your cut tree should be stood up in a large bucket of water in a shady and cool place as soon as you bring it home. If the tree must lean against a wall, make sure that you turn it daily to avoid disrupting the shape of the tree.