In "Biblical Perspective" Gordon Snider writes:
A vibrant spirit makes a new song out of old lyrics. New can mean “fresh” as well as new in time. Because the mercies of the Lord are “new every morning” (Lam. 3:23), our response must also be new, even if we use the same words. Play skillfully. The worship of God has no place for mediocrity. The word skillfully combines the ideas of doing an action well, and/or in a way that is pleasing to the observer. However we express our wor-ship, it must be in a way that brings joy to the heart of God. With a loud noise. The initial word of the Psalm emphasized the exuberance of the praise. Here again the word picture is of an alarm sounded, or the blast of a trumpet. We are urged to involve all our energy in the praise of our God.
Source: Studies in the Psalms: Adult Teacher's Insights, page 29.