Do not open doors to strangers. Keep windows covered at night and open during the day. If you hear or see something suspicious, call the police immediately. No defense method is guaranteed. Taking action quickly increases your chances of survival.
Common sense is valuable.
Practice the defensive techniques you choose to use. Anticipate as many scenarios as you can think of. Your action should be decisive and instinctive. Run away, preferably toward people. If you must fight, aim for the face, eyes, throat, or groin.