I’ve read of women leaving a strand or two of their hair in cabs/taxis (in case anything happened to them), also sending the registration to loved ones and describing the driver in a text.
Add the app ‘Find My‘ on your your phone, you can choose who you would like to be able to see your whereabouts, loved ones, family etc.
If you’re walking anywhere especially in the dark cross over the road when safe every now again on your journey, so you make it more difficult for someone to follow you, at least without you knowing.
Talk to someone on the phone if you’re walking in the dark, perhaps even detailing where you walking, street names, etc.
Carry a rape alarm and have it in your hand ready to use, especially if walking.
If someone is trying to abduct you, do whatever you can to get someone’s attention, even if it’s breaking something a window etc. Or if they’ve got hold of you knee, or kick them in the groin big time.
If you fall in the water try to remove heavy clothing/shoes while treading water with your feet. Try to stay calm as mad as that sounds, even lie on your back to keep you floating. If you can fill item of clothing with air by tying up the ends, then use it as a float. Added link to explain better what I mean.