Consider providing fencing or hedges around all yards and patios to provide privacy and to help define boundaries between public and private open space.

Low, wrought iron fences help define individual activity areas in this Oakland, California courtyard. 
(HismenHin-nu Terrace)

The fence in front of the Boulder, Colorado townhouse helps define the semi-private entry patio. Note how the style and materials of the fence mirror and reinforce the overall style and detailing of the unit as a whole. 
(Woodlands)

A picket fence provides privacy and, at the same time, reinforces the "single family home" character of this multi-unit building in Santa Monica, California. 
(Ocean Park Co-op)

Low, wrought iron fences define the front yards of these Chicago townhouses. At the same time they reinforce the boundary - common in other buildings on the street - between the public sidewalk and the semi-private yards. 
(West Town II)

Picket fences throughout this Stamford, Connecticut complex provide simple but clear separations between private patios and semi-public courtyards. At the same time they reinforce the overall architectural "style" of the complex. 
(Waterside Green)