Once you’ve enclosed the space you need to consider how to create atmosphere in it.
Water features are a great way of achieving that, especially if there are other noises nearby you have no control over, such as road traffic.
The sound of water can distract the mind away from less pleasant sounds. Fast flowing water stimulates the senses and creates a sense of adventure, whereas a slow trickle creates a more serene, relaxing atmosphere.
Old pieces of stone or fallen branches covered in moss strategically placed around the area are also a great addition as are plants that rustle in the wind or when you brush past them, such as grasses and bamboo.