To engage the world, a home should have an in-between space that beckons to the passersby while providing shelter and a perch from which to watch the street. This is a space, such as a porch, from which you can see the street, and the street can see you. Creating such a space is more than good manners and neighborliness — it also helps keep a neighborhood safe, as crime typically takes place in the shadows.
The in-between space is best when it's large enough to be a room of its own. A place for comfortable chairs, a table or two, maybe even a hammock. Remember that it is a room that's part of the home, so treat it with the same attention to detail as the other rooms. In fact, since this is the room that presents your face to the world, maybe treating it a little better than the other rooms is in order.
In a dense, urban setting, a balcony is like a front porch, a place from which to engage the world. Sure, these spaces are smaller and more detached from the street, yet they are still that great in-between place from which to greet neighbors and keep on eye on the neighborhood.
A small "box bay" that extends out over the sidewalk is also a perch from which to engage with the street and be a good neighbor.
Neighboring homes can be different. After all, who would want to live in a world where everything and everybody is the same? But please provide an overture to the surroundings. Maybe it's in the materials and colors, which don't shout out, "Look at me." Or maybe it's a window shape that's traditional, evoking something about what was there before.
Or maybe it's in the massing, which is similar to everything else nearby.
Being a good neighbor doesn't require a suburban or urban setting. A home set in the woods can be a good neighbor as well. It's really about how it responds to its site. Does it respect the landscape? Does it take in views? Does it allow for outdoor activities that celebrate its location? Remember, just because it has no neighbors doesn't mean that it's alone.
Don't pass up the opportunity to transform your home into a lantern that lights up the night and gives all a glimpse of the life inside. Homes that do this have a special place in my heart as they truly do enliven a street when all else is shut down and closed off.
And don't think of front porches as something that only traditionally designed homes can have. A modern aesthetic can celebrate community engagement just as well as any foursquare does.