There are several types of line in an arrangement. Lines can express different moods and feelings just by the direction they are placed. Line provides a pathway for the eye to follow throughout the arrangement. The three main types of line are actual line, implied line, and psychic line.
You could create an arrangement for any size vase, the larger the vase, the more flowers and greens to use. For Christmas time, use red, white and maybe even green flowers (like green button mums). Also choose from a variety of greens and evergreens out there. Accent a red rose in a bud vase with some baby's breath and cedar. Deep red alstroemeria are especially beautiful. There are many other flowers that would be perfect to use for Christmas arrangements, the link below will take you to a complete list of flowers, foliage, and evergreens for Christmas floral design.