I am not a doctor, so these suggestions are only speculations. So, don’t bother contacting me if you die trying these obviously experimental techniques.
Most people die of cardiovascular problems. Thus, of the seven billion people alive today, something approaching four billion people will die with blood clots and/or associated heart failure. The audience that might be helped by the suggestions below is large.
First, try to avoid dying by always carrying a few tablets of aspirin and have them available in five seconds. Check now! Can you have two aspirin in your mouth in five seconds? If you can’t do that, stop reading this right now, and go get two aspirin and put them in your wallet. Or put them in something you always have in your possession. Tape two aspirin to your computer where you can see it. That will remind you and your friends that your are ready. If you or your friend has a sudden onset of unusual pain, numbness, blanking of vision or other weird physical symptoms, take two aspirin. The main exception to this procedure is a bleeding brain problem, usually called TIA (Transient Ischemic Episode), but that risk is probably less than one in a hundred. Possibly there is an aspirin allergy, but that is unusual also.
The second thing to do, actually simultaneously, is to yell for help, and tell the person what your symptoms are having and to call the emergency doctor. Be quick about this, because your brain will only survive about five minutes without blood, and needless to say you won’t function well, without a good brain.
The third thing to do, actually simultaneously with the above suggestions, is to tighten your abdominal muscles at a rate of about once per second, like a strong cough, and keep breathing. That is said to keep enough blood flowing to your brain to maintain consciousness, and you can keep it up for quite a while. It will probably help to lie down on your back so most of your blood is at the same level as your brain. If your heart has stopped or is fibrillating wildly give your chest a whack with your fist about every ten seconds until it beats regularly. If it starts beating evenly stop whacking yourself, and squeezing your abdomen, but observe them carefully.
Obviously these are at home measures to be used until medical personnel can reach you, and take you to where there are much better treatments. If you can keep yourself alive for fifteen minutes, chances are you will be in as good a shape tomorrow as you were yesterday, but only if you get to the hospital alive.