Even if your neighborhood is more carcentric and suburban than walkable, diverse, and bustling, you can take steps to make it better--and become a better version of yourself in the process:
Get out on your front porch often. One of the most-important architectural elements for helping people become more civic-minded and engaged is the front porch. It provides opportunities to chat with your neighbors and interact with passersby. Start having your morning coffee, or your afternoon iced tea, on the front porch, and make a point to speak to (or at least smile at) the people walking by.
No front porch?--then hang out in the front yard. Get out and garden or rake the leaves on the street-facing side of your home. Have a picnic. Play tag with your kids. Read a book on the stoop. This gives you more opportunities to meet and interact with people in the neighborhood and keeps you aware of what is going on.
Do not put up a tall fence. Fences prevent all chance backyard encounters with your neighbors and also prevent everyone from keeping an eye out for each other. Whenever possible, choose lower and more-transparent fencing.
Ditch your car as often as possible and walk instead. Getting out and walking through your neighborhood, instead of driving, serves several purposes. First, it is a great opportunity to exercise, which helps you become your healthiest and most vital self, but it also helps you engage directly with your neighborhood and the people in it. Moving at a walking or biking pace, you will notice details you never would catch whizzing by in a car.
Involve apartment dwellers in neighborhood association meetings. Do not assume that people living in apartments care less about your neighborhood than homeowners. Invite them to public hearings and neighborhood meetings. They have just as much skin in the game as anyone else in the community.
Pick up garbage. People in emerging neighborhoods cannot always afford garbage bags. If you live in an up-and-coming area (and even if you do not), make a point to pick up trash you see when you are out and about. It is a quick and...