when i'm going to the parking lot at the hospital, late at night, i dial 911 on my phone, without pressing the "call" button. that way, if something happens to me, all i have to do is push the button (twice, on my phone--to "confirm" the call). i have made sure the "location/gps" setting is on as well, so the phone can give an indication of where i was last located. always walk as though you have a destination in mind--never appear "tentative" when you are out. and although the facial bones are tough, the nose is vulnerable. heel of the hand to a nose, front and center, will damage and disable. the throat shot with the fist of side or the hand may even fracture the hyoid bone in their larynx. this is a good thing in self defense. if you have been attacked, don't even think about "reviving" them. their intent is to damage, kidnap, rob, or kill you. my intent is to keep living.
another tactic is the "crazy" approach. if you are in a situation that is dicey, if you act crazy, talk to yourself, loudly, act oddly (while in a protective mode) people give you a wide berth. very few people will mess with a crazy--the victim may be crazier than they are...
i still own the victorian hatpin my grandmother gave me for a "ladylike" self defense back when i was a teenager. i still carry it, on occasion...it's nearly invisible, and fits into a clutch purse.