Never talk on the phone to people you don't know. If harassing calls become persistent or threatening, report them to the police immediately. Find someone to walk with you when going out at night. Whether walking at night or during the day, don't wear headphones, or otherwise cut yourself off from what's going on around you. Don't wander into dark places or unfamiliar areas.
Alcohol impairs a person's ability to appraise and react to situations.
Whether it's a suspicious person, harassing phone calls, theft, or some other unsettling incident, make sure you report it to police immediately. If you are a victim of crime, or see someone behaving in a suspicious manner, be sure to call the police immediately. Try to get the best possible description of the suspect in order to aid police in responding to your call. Start with the suspect's head and work down, noticing as many details as you can. If the crime just occurred, or is still in progress, give the description to the dispatcher when calling.