Groin kicks are never as effective as knee or ankle kicks, even stomps to the top of the foot ... break the leg of your opponent and you can easily get away or call the cops and wait while they can not get away ... but a groin kick only causes some extreme pain for a while, and then, a few moments later, your opponent is right back ready to fight some more.

My first impression is that your instructions are too specific. The sort of self-protection instruction manual that defines set techniques, usually doesn't understand what's going on at a time when people need to use those skills. Far too many courses or books follow a set of "grab here, strike here like this, push here" instructions, that break down when not in controlled conditions. Most people who get brief instruction into self protection are not martial artists, and even most martial artists are not that precise in an actual encounter. For an easy to find example, check some videos of people put into sparring matches: for the majority of them, any technique they had breaks down. Once you're past the key parts of self protection: observation, confidence, prevention & planning, you're left with what to actually fight with. What's important for people to understand, and usually the only message they'll really take away, is that striking can work. They'll get an impression of what striking another person is like. Martial artists like to cover the different styles of kicks, but to a self defense audience the message isn't precision. The message is the fact that you don't have to be precise - any of the surfaces of the foot and leg will have an impact, you don't need to worry about which ends up making contact. Any of the targets in this general area will be good, don't worry too much if you miss a specific part. It's driving home the message that you don't have to be a good fighter, you just have to do something, and that doing anything is better than doing nothing. So, for a self-defense instructable, kicking boils down to "Make contact with something solid of yours, like the foot or knee, and go for something that's easy to reach. Good places to think about are: side of the knee, ankle, top of the foot, or any bit that's easy to reach. If you make contact, hit it over and over again."

For general application of self def. one should attack the weapon not the person, If they are a kicker break the leg, a puncher the arm etc. Attacks to the joints are best because they are difficule to defend aginst. wrist, elbow, knee, sholder, ankle, fingers,etc. are easy to damage. Bone, tendon and mussel, nerves are harder to attack and require special training.