Mindfully acknowledge that you are powerless to change nature. In nature, the strong prevail. We are all the spawn of millions of years of natural selection. You are a survivor. Act accordingly.
It doesn't matter if you personally like it or not. If you appear weak, distracted or outside the norm, you present yourself as a victim. Predators are watching.
Slack jawed, round shouldered, eyes down, weighed down with packages, fumbling with a map, dressed like Lady Gaga or Urkle, you draw attention to yourself in a negative way with eventual negative consequences.
Don't do that. Don't appear distracted talking on your cellphone, texting or wearing headphones.
Your body language is important. Think cool, calm, confident and even bored. Bored and disinterested projects the opposite of appearing nervous. Look like a serious person with a purpose. Look like someone who will fight back. Let him take a look and be afraid of you. Be scary. Have looks that could kill. Most predators are looking for an easy score and not a physical confrontation.
Stand up straight, steady, sure. Look people in the eye without staring. Dress appropriately to the situation. Relax your hands. Lower your breathing.
All that is needed for evil to triumph is for good men to do nothing.