TIP #2 - ALWAYS HAVE A TOOL HANDY
Always, always, always have something easily and quickly accessible to use as a weapon. Note that I did not say, "have a weapon accessible" which is not always practical or advisable. If someone surprises you, there should be something instantly accessible to aid in your defense. CBG Safety sells a number of simple self-defense objects.

Anything you find that is hard and fast should be aimed at smashing against something made of bone, 
and anything with a point to it should be aimed at stabbing into soft tissue.