The main points, you have already covered. Carrying tools and a cell phone, leaving your ride info with others, road id, staying aware. Good points. There is only so much one can do, short of riding around in a suit of armor with a gaggle of bodyguards behind you.
The two things that become most important in an emergency where you may have to take action are TIME and DISTANCE. Each provides the other. Time to react- put on the brakes, call 911, reverse direction, head for a neighbors house. Distance-removal from threat or danger provides the time to think through what you need to do. Being aware is probably the most important thing at any time you are in public. This will provide distance and time. When I was aware I was being followed in my car, it gave me the time to react, the time to think. It gave me distance, as I was not hemmed in my driveway- I was a few miles from home on a public street and still in my car driving. That distance gave me some time and I was able to use that time to formulate a plan that kept myself, and my family at home, safe. I reversed direction and they turned around and followed me all the way to the parking lot of the Highway patrol.
So it may seem simplistic. But being aware is probably the best thing we can all do. Those YouTube videos of people falling down stairs and onto train tracks as they are obliviously texting may be funny, but they underscore my point. Without awareness nothing else matters.
Pepper spray may be better than nothing if you know how to use it and YES go out to an empty field, setup a target at the recommended distance and USE it. SEE how it sprays out, can you point it well? Did you just spray some attacker in the neck or chest and piss him off (not a good idea) or did you hit him in the face with it. Can you do that under stress with your heart pounding as you are running? Pepperspray is a REACTION. You are already in trouble. Best not to be in that situation if possible. Awareness first. If the place you are in is making the hairs on the back of your neck stand up- listen to yourself and get out of there. I thought I was being silly at first when I was being followed home by a car with 4 young men playing rap music. But my gut told me to watch them, and I began to zig zag through main streets and they followed. No more silly- react now before trouble starts.
Sorry for the long post, but you can see I have spent some time dwelling on this myself. Not just for cycling, but for my daily life. I don't listen to music or text as I walk about, cycle or drive. I try to be aware. I look in the back seat before opening the car door, I close and lock the door immediately when I get in, and remain aware of who else is around me. I cycle on roads that are well traveled, and that I am familiar with. When on vacation I have gone over the maps before leaving and have a GPS and always know where I am. When MTBing alone, I skip the more fun less traveled trails and stick to the trails that have equestrian and hiking traffic along with other cycle traffic.
It can be tough to remain alert and all too easy to just zone out with Twitter or other such nonsense.
Tzvia- rollin' slow...
Specialized Ruby Expert/mens Bontrager Inform RXL
Specialized SWorks Safire/mens Bontrager Inform RL
Giant Anthem-W XT-XTR/mens Bontrager Inform RXL
Fuji Newest 3 commuter/mens Bontrager Inform RL
Novara E.T.A commuter/mens Bontrager Inform RL