The most important thing to learn in martial arts class is self confidence. If a person wants to harm you, he is going to size you up first. If you show air of confidence or calmness then he will more likely leave you alone.

Don't think for one moment that you can "hand chop" your way through a confrontation. I think good self-defense class will teach you on how to defuse the situation first or to minimize your risk and only when you have no other recourse should you try with physical force. Take a camera phone with 3G connection so you can send photos immediately. Take necessary precaution before going in. Call in to say you are at the site and going in. Check in every 5, 10, 15 minutes. Call in when you come out to say you are safely back on the road.

Much of modern culture and especially ours says to take things "squarely on", "head-on". And this generally is not a best approach when dealing with potential adversary.

Best fight is not engaging in fight. Learn body language for sign of hostility and how to defuse it. Walk away and disengage is the best option.

You will find these idea in "Art of War" by Sun Tsu. written around 300BC. Short but very much to the point. Understanding will help you with dangerous situations. I think you can get it on kindle for free or for very cheap.