All but the smallest gardens need an element of mystery. One of the most effective ways to give a small garden a bit of mystery is to have a small fountain which can be heard throughout the garden, but which is hidden from most of the garden. Humans, like most animals, have a natural inclination to look for the source of running water. In a large garden, water can be used to unify areas with contrasting moods. To do this you will need to have a water feature in each area.
Water can express a number of moods.
Still water is serene, fountains are theatrical, water rushing over rocks is exuberant. Water features can help to create contrasting moods while they unify a garden. Gardens can be predominately introverted or extroverted. An extroverted garden is one which is open to view. If it is open to view from a public highway, it is very extroverted.