Best safety precaution?

I live in a BAD neighborhood alone, and about a week ago someone tried to break into my apartment. The only reason it's a bad neighborhood is because it is yards away from this trashy strip club with a motel beside it full of junkies and prostitutes. When I accidentally do make the mistake of staying out after dark all I have is a small container of mase. Also this next semester I will be taking night classes that don't end until 10:00pm. What would be the best defense for me against possible predators.