Three rules of self defense, as taught by my instructor in Tae Kwon Do:
1. If the enemy cannot see, he cannot fight. Strike the eyes, of the bridge of the nose.
2. If the enemy cannot breathe, he cannot fight. Strike the diaphragm.
3. If the enemy cannot stand, he cannot fight. Strike the knees.
Good advice 20 years ago, and it has stood the test of time.
4. Fight dirty as if your life depended on it. Groin. Fingers in eyes. Bite like hell. Head butt. Dislocate knee, elbow. Cup hands and slap ears full strength. Fingers deep into space between earlobe and jaws. Smash foot with heel of shoe to break foot.
Most vulnerable: Throat, groin, eyes.