Once you have a location, consider what structures or plants could be added or removed. A gazebo, a potting shed, a deck, a treehouse or a porch suggest relaxation. Pavers, flagstone or other hard surfaces can indicate a separate place. Or, as part of the sanctuary, you might consider adding something as simple as a lattice screen with vines. Note the protection offered by buildings, wind patterns and availability of water.
Water suggests peace, and water gardens are popular.
Garden centers and publications can provide a lot of help in using water effectively. Water features can range from something as simple as a container water garden to a complex waterfall and pond. Add personal touches that please you. An interesting stump or bench for seating, a table for coffee or a chest for writing materials or candles could be just the thing. Consider fragrant blossoms to soothe the senses or plants with morning or night blooms.